diff --git a/AuraTrader/MainForm.pas b/AuraTrader/MainForm.pas
index c236e08..f9f870e 100644
--- a/AuraTrader/MainForm.pas
+++ b/AuraTrader/MainForm.pas
@@ -897,7 +897,7 @@ begin
         exit;
 
     var timeframe := TTimeframe.M15;
-    ExecuteStrategy(Symbol, timeframe, CreateStrategy2(timeframe));
+    //    ExecuteStrategy(Symbol, timeframe, CreateStrategy2(timeframe));
 
     var tstStrat := StrategyTest.CreateStrategy1(timeframe);
     ExecuteStrategy(Symbol, timeframe, tstStrat);
diff --git a/Src/Myc.Trade.DataArray.pas b/Src/Myc.Trade.DataArray.pas
index e4db488..a3d618c 100644
--- a/Src/Myc.Trade.DataArray.pas
+++ b/Src/Myc.Trade.DataArray.pas
@@ -3,10 +3,7 @@ unit Myc.Trade.DataArray;
 interface
 
 type
-    // A series is an array of values with the newest ite at index=0. Each series counts the total of added items since creation, but
-    // it actually may contain less items, because the array size is limited by the lookback parameter, when adding items.
-    // Series are immutable.
-    TSeries<T> = record
+    TChunkArray<T> = record
     private
         const
             ChunkSize = 1024;
@@ -14,118 +11,390 @@ type
             TChunk = TArray<T>;
     private
         FChunks: TArray<TChunk>;
-        FCount: Int64;
-        FTotalCount: Int64;
+        FOffset: Integer;
+        FCount: Integer;
+        function GetItems(Idx: Integer): T; inline;
 
-        function LogicalToPhysicalIndex(LogicalIndex: Int64): Int64; inline;
-        function GetItems(Idx: Int64): T; inline;
     public
-        constructor Create(const AChunks: TArray<TChunk>; ACount, ATotalCount: Int64);
+        constructor Create(const AChunks: TArray<TChunk>; ACount: Integer; AOffset: Integer);
+        class operator Initialize(out Dest: TChunkArray<T>);
 
+        // Add a single item without creating a temporary array.
+        procedure Add(const Data: T; MaxCount: Integer); overload;
+
+        // Add items, but ensure that the result has MaxCount items.
+        procedure Add(const Data: array of T; MaxCount: Integer); overload;
+
+        class function CreateFromArray(const AData: TArray<T>; MaxCount: Integer): TChunkArray<T>; static;
+
+        // Creates a deep copy of the array, optionally truncating it to the last MaxCount items.
+        function Copy(MaxCount: Integer = -1): TChunkArray<T>;
+
+        property Count: Integer read FCount;
+        property Items[Idx: Integer]: T read GetItems; default;
+    end;
+
+    // A series where the last added item has index 0.
+    TSeries<T> = record
+    private
+        FArray: TChunkArray<T>;
+        FTotalCount: Int64;
+        function GetCount: Integer;
+        function GetItems(Idx: Integer): T;
+
+    public
+        constructor Create(const AArray: TChunkArray<T>; ATotalCount: Int64);
         class operator Initialize(out Dest: TSeries<T>);
-        // Add a singe item
-        function Add(const Data: T; Lookback: Int64 = -1): TSeries<T>; overload;
-        // Add a ranmge of items
-        function Add(const Data: array of T; First, Count, Lookback: Int64): TSeries<T>; overload;
-        // Helper to create a data array from a raw TArray.
-        class function CreateFromArray(const AData: TArray<T>; First, Count: Integer): TSeries<T>; static;
-        property Count: Int64 read FCount;
+
+        // Creates a deep copy of the series, optionally truncating it to the last Lookback items.
+        function Copy(Lookback: Integer = -1): TSeries<T>;
+
+        procedure Add(const Data: T; Lookback: Int64 = -1); overload;
+        procedure Add(const Data: array of T; Lookback: Integer); overload;
+
+        class function CreateFromArray(const AData: TArray<T>; Lookback: Integer): TSeries<T>; static;
+
+        property Count: Integer read GetCount;
         property TotalCount: Int64 read FTotalCount;
-        property Items[Idx: Int64]: T read GetItems; default;
+        property Items[Idx: Integer]: T read GetItems; default;
     end;
 
 implementation
 
 uses
+    System.Generics.Collections,
     System.Math;
 
-{ TSeries<T> }
+{ TChunkArray<T> }
 
-constructor TSeries<T>.Create(const AChunks: TArray<TChunk>; ACount, ATotalCount: Int64);
+constructor TChunkArray<T>.Create(const AChunks: TArray<TChunk>; ACount, AOffset: Integer);
 begin
     FChunks := AChunks;
     FCount := ACount;
-    FTotalCount := ATotalCount;
+    FOffset := AOffset;
+    Assert(FOffset < ChunkSize);
 end;
 
-class function TSeries<T>.CreateFromArray(const AData: TArray<T>; First, Count: Integer): TSeries<T>;
-begin
-    // Use the Add method on an empty array to perform the chunking logic.
-    Result.Add(AData, First, Count, Count);
-end;
-
-function TSeries<T>.Add(const Data: array of T; First, Count, Lookback: Int64): TSeries<T>;
+procedure TChunkArray<T>.Add(const Data: T; MaxCount: Integer);
 var
-    destPhysicalIdx, sourcePhysicalIdx: Int64;
-    itemsToSkip: Int64;
-    numNewChunks: Integer;
-    newChunks: TArray<TChunk>;
-    destChunkIdx, destSubIdx: Integer;
-    sumCount, newCount: Int64;
+    newCount, totalNewOffset: Integer;
+    oldLogicalEnd, newLogicalEnd, oldStartChunk, newStartChunk, oldEndChunk, newEndChunk, chunksToRemove, chunksToAdd: Integer;
 begin
-    if Count < 0 then
-        Count := Length(Data) - First;
-    if Count = 0 then
-        exit(Self);
+    if MaxCount < 0 then
+        MaxCount := MaxInt;
 
-    Assert(Count <= (Length(Data) - First), 'Count cannot be larger than the source array');
+    if MaxCount <= 0 then
+        exit;
 
-    sumCount := FCount + Count;
-    newCount := sumCount;
-    if (Lookback >= 0) and (newCount > Lookback) then
-        newCount := Lookback;
-    itemsToSkip := sumCount - newCount;
+    // 1. Calculate the new logical state (numToAdd is always 1)
+    newCount := Min(FCount + 1, MaxCount);
+    totalNewOffset := FOffset + FCount + 1 - newCount;
 
-    numNewChunks := 0;
+    // 2. Determine if the underlying FChunks array needs restructuring
+    oldLogicalEnd := FOffset + FCount - 1;
+    newLogicalEnd := totalNewOffset + newCount - 1;
+
+    oldStartChunk := FOffset div ChunkSize;
+    newStartChunk := totalNewOffset div ChunkSize;
+
+    oldEndChunk := -1;
+    if FCount > 0 then
+        oldEndChunk := oldLogicalEnd div ChunkSize;
+
+    newEndChunk := -1;
     if newCount > 0 then
-        numNewChunks := (newCount - 1) div ChunkSize + 1;
-    SetLength(newChunks, numNewChunks);
+        newEndChunk := newLogicalEnd div ChunkSize;
 
-    for destPhysicalIdx := 0 to newCount - 1 do
+    chunksToRemove := newStartChunk - oldStartChunk;
+    chunksToAdd := newEndChunk - oldEndChunk;
+
+    // 3. Perform the add operation
+    if (chunksToRemove > 0) or (chunksToAdd > 0) then
     begin
-        destChunkIdx := destPhysicalIdx div ChunkSize;
-        destSubIdx := destPhysicalIdx mod ChunkSize;
+        // --- Rebuild Path: Chunks must be added or removed ---
+        var newChunks: TArray<TChunk>;
+        var oldChunkCount := Length(FChunks);
+        var newChunkCount := oldChunkCount - chunksToRemove + chunksToAdd;
+        SetLength(newChunks, newChunkCount);
 
-        if destSubIdx = 0 then
-            SetLength(newChunks[destChunkIdx], ChunkSize);
+        var numChunksToKeep := oldChunkCount - chunksToRemove;
+        if numChunksToKeep > 0 then
+            TArray.Copy<TChunk>(FChunks, newChunks, chunksToRemove, 0, numChunksToKeep);
 
-        sourcePhysicalIdx := itemsToSkip + destPhysicalIdx;
+        for var i := numChunksToKeep to newChunkCount - 1 do
+            SetLength(newChunks[i], ChunkSize);
 
-        if sourcePhysicalIdx < FCount then
+        FChunks := newChunks;
+
+        // Copy the new data item into the rebuilt chunks
+        var writeStartLogicalIdx := FOffset + FCount;
+        var physicalWriteStartIdx := writeStartLogicalIdx - (chunksToRemove * ChunkSize);
+        var chunkIdx := physicalWriteStartIdx div ChunkSize;
+        var idxInChunk := physicalWriteStartIdx mod ChunkSize;
+
+        Assert(chunkIdx < Length(FChunks), 'Chunk index out of bounds during rebuild');
+        FChunks[chunkIdx][idxInChunk] := Data;
+    end
+    else
+    begin
+        // --- Fast Path: Window slides within existing chunk allocation ---
+        var writeStartLogicalIdx := FOffset + FCount;
+        var chunkIdx := writeStartLogicalIdx div ChunkSize;
+        var idxInChunk := writeStartLogicalIdx mod ChunkSize;
+
+        Assert(chunkIdx < Length(FChunks), 'Chunk index out of bounds on fast path');
+        if Length(FChunks[chunkIdx]) = 0 then // Safeguard
+            SetLength(FChunks[chunkIdx], ChunkSize);
+
+        FChunks[chunkIdx][idxInChunk] := Data;
+    end;
+
+    // 4. Finalize the new state
+    FOffset := totalNewOffset mod ChunkSize;
+    FCount := newCount;
+end;
+
+class function TChunkArray<T>.CreateFromArray(const AData: TArray<T>; MaxCount: Integer): TChunkArray<T>;
+begin
+    Result.Add(AData, MaxCount);
+end;
+
+procedure TChunkArray<T>.Add(const Data: array of T; MaxCount: Integer);
+var
+    dataLen, dataReadOffset, numToAdd, newCount, totalNewOffset: Integer;
+    oldLogicalEnd, newLogicalEnd, oldStartChunk, newStartChunk, oldEndChunk, newEndChunk, chunksToRemove, chunksToAdd: Integer;
+begin
+    if MaxCount < 0 then
+        MaxCount := MaxInt;
+
+    dataLen := Length(Data);
+    if (dataLen = 0) or (MaxCount <= 0) then
+        exit;
+
+    // 1. Trim input data if it's larger than MaxCount
+    dataReadOffset := 0;
+    if dataLen > MaxCount then
+        dataReadOffset := dataLen - MaxCount;
+    numToAdd := dataLen - dataReadOffset;
+
+    // 2. Calculate the new logical state (total offset and count)
+    newCount := Min(FCount + numToAdd, MaxCount);
+    // Total logical offset of the new window's start
+    totalNewOffset := FOffset + FCount + numToAdd - newCount;
+
+    // 3. Determine if the underlying FChunks array needs restructuring
+    oldLogicalEnd := FOffset + FCount - 1;
+    newLogicalEnd := totalNewOffset + newCount - 1;
+
+    oldStartChunk := FOffset div ChunkSize;
+    newStartChunk := totalNewOffset div ChunkSize;
+
+    oldEndChunk := -1;
+    if FCount > 0 then
+        oldEndChunk := oldLogicalEnd div ChunkSize;
+
+    newEndChunk := -1;
+    if newCount > 0 then
+        newEndChunk := newLogicalEnd div ChunkSize;
+
+    chunksToRemove := newStartChunk - oldStartChunk;
+    chunksToAdd := newEndChunk - oldEndChunk;
+
+    // 4. Perform the add operation
+    if (chunksToRemove > 0) or (chunksToAdd > 0) then
+    begin
+        // --- Rebuild Path: Chunks must be added or removed ---
+        var newChunks: TArray<TChunk>;
+        var oldChunkCount := Length(FChunks);
+        var newChunkCount := oldChunkCount - chunksToRemove + chunksToAdd;
+        SetLength(newChunks, newChunkCount);
+
+        // Copy references to the chunks that are kept
+        var numChunksToKeep := oldChunkCount - chunksToRemove;
+        if numChunksToKeep > 0 then
+            TArray.Copy<TChunk>(FChunks, newChunks, chunksToRemove, 0, numChunksToKeep);
+
+        // Allocate new chunks at the end
+        for var i := numChunksToKeep to newChunkCount - 1 do
+            SetLength(newChunks[i], ChunkSize);
+
+        FChunks := newChunks;
+
+        // Copy the new data into the rebuilt chunks
+        var writeStartLogicalIdx := FOffset + FCount;
+        var physicalWriteStartIdx := writeStartLogicalIdx - (chunksToRemove * ChunkSize);
+        var remainingToAdd := numToAdd;
+        var currentDataOffset := dataReadOffset;
+
+        while remainingToAdd > 0 do
         begin
-            newChunks[destChunkIdx][destSubIdx] := FChunks[sourcePhysicalIdx div ChunkSize][sourcePhysicalIdx mod ChunkSize];
-        end
-        else
+            var chunkIdx := physicalWriteStartIdx div ChunkSize;
+            var idxInChunk := physicalWriteStartIdx mod ChunkSize;
+            var spaceInChunk := ChunkSize - idxInChunk;
+            var countToCopy := Min(remainingToAdd, spaceInChunk);
+
+            Assert(chunkIdx < Length(FChunks), 'Chunk index out of bounds during rebuild');
+            TArray.Copy<T>(Data, FChunks[chunkIdx], currentDataOffset, idxInChunk, countToCopy);
+
+            inc(physicalWriteStartIdx, countToCopy);
+            inc(currentDataOffset, countToCopy);
+            dec(remainingToAdd, countToCopy);
+        end;
+    end
+    else
+    begin
+        // --- Fast Path: Window slides within existing chunk allocation ---
+        var writeStartLogicalIdx := FOffset + FCount;
+        var remainingToAdd := numToAdd;
+        var currentDataOffset := dataReadOffset;
+
+        while remainingToAdd > 0 do
         begin
-            newChunks[destChunkIdx][destSubIdx] := Data[First + (sourcePhysicalIdx - FCount)];
+            var chunkIdx := writeStartLogicalIdx div ChunkSize;
+            var idxInChunk := writeStartLogicalIdx mod ChunkSize;
+            var spaceInChunk := ChunkSize - idxInChunk;
+            var countToCopy := Min(remainingToAdd, spaceInChunk);
+
+            Assert(chunkIdx < Length(FChunks), 'Chunk index out of bounds on fast path');
+            if Length(FChunks[chunkIdx]) = 0 then // Should not happen on fast path, but as a safeguard
+                SetLength(FChunks[chunkIdx], ChunkSize);
+
+            TArray.Copy<T>(Data, FChunks[chunkIdx], currentDataOffset, idxInChunk, countToCopy);
+
+            inc(writeStartLogicalIdx, countToCopy);
+            inc(currentDataOffset, countToCopy);
+            dec(remainingToAdd, countToCopy);
         end;
     end;
 
-    Result := TSeries<T>.Create(newChunks, newCount, FTotalCount + Count);
+    // 5. Finalize the new state
+    FOffset := totalNewOffset mod ChunkSize;
+    FCount := newCount;
 end;
 
-function TSeries<T>.Add(const Data: T; Lookback: Int64): TSeries<T>;
+function TChunkArray<T>.GetItems(Idx: Integer): T;
 begin
-    Result := Add([Data], 0, 1, Lookback);
+    // Convert logical index to physical index inside chunks
+    var physicalIdx := Idx + FOffset;
+    Result := FChunks[physicalIdx div ChunkSize][physicalIdx mod ChunkSize];
 end;
 
-function TSeries<T>.GetItems(Idx: Int64): T;
+function TChunkArray<T>.Copy(MaxCount: Integer): TChunkArray<T>;
 var
-    physicalIndex: Int64;
+    effectiveCount: Integer;
+    logicalStartIndex: Integer;
+    physicalStartIndex, physicalEndIndex: Integer;
+    startChunkIdx, endChunkIdx: Integer;
+    newOffset: Integer;
+    newChunkCount: Integer;
+    i: Integer;
 begin
-    Assert((Idx >= 0) and (Idx < FCount), 'Logical index is out of bounds.');
-    physicalIndex := LogicalToPhysicalIndex(Idx);
-    Result := FChunks[physicalIndex div ChunkSize][physicalIndex mod ChunkSize];
+    // 1. Determine the number of items to copy.
+    effectiveCount := FCount;
+    if (MaxCount >= 0) and (MaxCount < FCount) then
+        effectiveCount := MaxCount;
+
+    if effectiveCount = 0 then
+    begin
+        // Return an empty array.
+        Result := Default(TChunkArray<T>);
+        exit;
+    end;
+
+    // 2. Calculate physical location of the data to be copied.
+    logicalStartIndex := FCount - effectiveCount;
+    physicalStartIndex := FOffset + logicalStartIndex;
+    physicalEndIndex := physicalStartIndex + effectiveCount - 1;
+    startChunkIdx := physicalStartIndex div ChunkSize;
+    endChunkIdx := physicalEndIndex div ChunkSize;
+    newOffset := physicalStartIndex mod ChunkSize;
+
+    // 3. Create the new chunk array for the result.
+    newChunkCount := endChunkIdx - startChunkIdx + 1;
+    SetLength(Result.FChunks, newChunkCount);
+
+    // 4. Copy chunks. Boundary chunks are deep-copied, internal chunks are shared.
+    if newChunkCount = 1 then
+    begin
+        // All data is in a single chunk, which is both a start and end boundary.
+        // It must always be a deep copy.
+        Result.FChunks[0] := System.Copy(FChunks[startChunkIdx]);
+    end
+    else
+    begin
+        // First chunk (start boundary) must be a deep copy.
+        Result.FChunks[0] := System.Copy(FChunks[startChunkIdx]);
+
+        // Middle, immutable chunks can be shared by reference.
+        // This loop only runs if there are 3 or more chunks in the copy.
+        for i := 1 to newChunkCount - 2 do
+        begin
+            Result.FChunks[i] := FChunks[startChunkIdx + i];
+        end;
+
+        // Last chunk (end boundary) must be a deep copy.
+        Result.FChunks[newChunkCount - 1] := System.Copy(FChunks[endChunkIdx]);
+    end;
+
+    // 5. Finalize the new TChunkArray state.
+    Result.FOffset := newOffset;
+    Result.FCount := effectiveCount;
 end;
 
-function TSeries<T>.LogicalToPhysicalIndex(LogicalIndex: Int64): Int64;
+class operator TChunkArray<T>.Initialize(out Dest: TChunkArray<T>);
 begin
-    Result := FCount - LogicalIndex - 1;
+    Dest.FOffset := 0;
+    Dest.FCount := 0;
+end;
+
+{ TSeries<T> }
+
+procedure TSeries<T>.Add(const Data: T; Lookback: Int64);
+begin
+    FArray.Add(Data, Lookback);
+    inc(FTotalCount);
+end;
+
+procedure TSeries<T>.Add(const Data: array of T; Lookback: Integer);
+begin
+    FArray.Add(Data, Lookback);
+    inc(FTotalCount, Length(Data));
+end;
+
+constructor TSeries<T>.Create(const AArray: TChunkArray<T>; ATotalCount: Int64);
+begin
+    FArray := AArray;
+    FTotalCount := ATotalCount;
+end;
+
+function TSeries<T>.Copy(Lookback: Integer): TSeries<T>;
+begin
+    // Create a copy of the underlying chunk array, optionally truncating it.
+    Result.FArray := FArray.Copy(Lookback);
+    // The new series' total count is the number of items it actually contains.
+    Result.FTotalCount := Result.FArray.Count;
+end;
+
+class function TSeries<T>.CreateFromArray(const AData: TArray<T>; Lookback: Integer): TSeries<T>;
+begin
+    Result.FArray.Add(AData, Lookback);
+    Result.FTotalCount := Length(AData);
+end;
+
+function TSeries<T>.GetCount: Integer;
+begin
+    Result := FArray.Count;
+end;
+
+function TSeries<T>.GetItems(Idx: Integer): T;
+begin
+    // Access is reversed: series index 0 is the last element in the underlying array
+    Assert((Idx >= 0) and (Idx < FArray.Count), 'Index out of bounds');
+    Result := FArray.Items[FArray.Count - 1 - Idx];
 end;
 
 class operator TSeries<T>.Initialize(out Dest: TSeries<T>);
 begin
-    Dest.FCount := 0;
     Dest.FTotalCount := 0;
 end;
 
diff --git a/Src/Myc.Trade.DataPoint.Impl.pas b/Src/Myc.Trade.DataPoint.Impl.pas
index b675a73..776ea49 100644
--- a/Src/Myc.Trade.DataPoint.Impl.pas
+++ b/Src/Myc.Trade.DataPoint.Impl.pas
@@ -554,7 +554,7 @@ begin
                 end;
                 Assert(FCount = 0);
 
-                Value := Value.Add(Arr, 0, Length(Arr), FLookback);
+                Value.Add(Arr, FLookback);
             end;
         end;
     finally
diff --git a/Src/Myc.Trade.Indicators.pas b/Src/Myc.Trade.Indicators.pas
index 99e0484..ff14828 100644
--- a/Src/Myc.Trade.Indicators.pas
+++ b/Src/Myc.Trade.Indicators.pas
@@ -216,7 +216,7 @@ begin
         var
             stdDev: Double;
         begin
-            sourceData := sourceData.Add(Value, Period);
+            sourceData.Add(Value, Period);
             Result.MiddleBand := Double.NaN;
             Result.UpperBand := Double.NaN;
             Result.LowerBand := Double.NaN;
@@ -240,7 +240,7 @@ begin
     Result :=
         function(const Value: Double): Double
         begin
-            sourceData := sourceData.Add(Value, Period);
+            sourceData.Add(Value, Period);
 
             if (sourceData.Count < Period) then
             begin
@@ -281,7 +281,7 @@ begin
             Result := Double.NaN;
 
             // Add new price to the source data array, respecting the lookback period.
-            sourceData := sourceData.Add(price, Period);
+            sourceData.Add(price, Period);
 
             // Check if there is enough data to start the first stage of calculation.
             if (sourceData.Count >= Period) then
@@ -292,7 +292,7 @@ begin
 
                 // Calculate the difference and add to the intermediate series.
                 diff := 2 * wmaHalf - wmaFull;
-                diffSeries := diffSeries.Add(diff, periodSqrt);
+                diffSeries.Add(diff, periodSqrt);
 
                 // Check if there is enough intermediate data for the final calculation.
                 if (diffSeries.Count >= periodSqrt) then
@@ -352,7 +352,7 @@ begin
             gainSum, lossSum: Double;
             i: Integer;
         begin
-            sourceData := sourceData.Add(Value, Period + 1);
+            sourceData.Add(Value, Period + 1);
             Result := Double.NaN;
 
             if (sourceData.Count <= Period) then
@@ -404,7 +404,7 @@ begin
     Result :=
         function(const Value: Double): Double
         begin
-            sourceData := sourceData.Add(Value, Period);
+            sourceData.Add(Value, Period);
             if (sourceData.Count >= Period) then
                 Result := CalculateSMA(sourceData, Period)
             else
@@ -432,7 +432,7 @@ begin
             i: Integer;
             highestHigh, lowestLow: Double;
         begin
-            sourceData := sourceData.Add(Value, KPeriod);
+            sourceData.Add(Value, KPeriod);
             Result.K := Double.NaN;
             Result.D := Double.NaN;
 
@@ -477,7 +477,7 @@ begin
             tr: Double;
         begin
             // We only need the previous bar to calculate true range.
-            sourceData := sourceData.Add(Value, 2);
+            sourceData.Add(Value, 2);
 
             if (sourceData.Count < 2) then
             begin
diff --git a/Test/MycTests.dpr b/Test/MycTests.dpr
index 81ac9d0..6c9b172 100644
--- a/Test/MycTests.dpr
+++ b/Test/MycTests.dpr
@@ -30,7 +30,8 @@ uses
     Myc.Trade.DataStream in '..\Src\Myc.Trade.DataStream.pas',
     Myc.Mutable in '..\Src\Myc.Mutable.pas',
     Test.Core.Mutable in 'Test.Core.Mutable.pas',
-    TestDataRecord in 'TestDataRecord.pas';
+    TestDataRecord in 'TestDataRecord.pas',
+    TestDataArray in 'TestDataArray.pas';
 
 { keep comment here to protect the following conditional from being removed by the IDE when adding a unit }
 {$IFNDEF TESTINSIGHT}
diff --git a/Test/MycTests.dproj b/Test/MycTests.dproj
index b6f3939..a39e1fe 100644
--- a/Test/MycTests.dproj
+++ b/Test/MycTests.dproj
@@ -132,6 +132,7 @@ $(PreBuildEvent)]]></PreBuildEvent>
         <DCCReference Include="..\Src\Myc.Mutable.pas"/>
         <DCCReference Include="Test.Core.Mutable.pas"/>
         <DCCReference Include="TestDataRecord.pas"/>
+        <DCCReference Include="TestDataArray.pas"/>
         <BuildConfiguration Include="Base">
             <Key>Base</Key>
         </BuildConfiguration>
diff --git a/Test/TestDataArray.pas b/Test/TestDataArray.pas
new file mode 100644
index 0000000..ab85bed
--- /dev/null
+++ b/Test/TestDataArray.pas
@@ -0,0 +1,210 @@
+unit TestDataArray;
+
+interface
+
+uses
+    System.SysUtils,
+    DUnitX.TestFramework,
+    Myc.Trade.DataArray;
+
+type
+    [TestFixture]
+    TMyTestObject = class
+    private
+        function GenerateData(Count: Integer): TArray<Integer>;
+    public
+        [Test]
+        [TestCase('Small_NoSlide', '100, -1')]
+        [TestCase('Small_WithSlide', '100, 50')]
+        [TestCase('Medium_NoSlide_CrossChunk', '1500, -1')]
+        [TestCase('Medium_WithSlide_CrossChunk', '2500, 1500')]
+        [TestCase('Large_ExactSlide', '5000, 1024')]
+        procedure TestChunkArray_CreateFromArray(const DataSize, MaxCount: Integer);
+
+        [Test]
+        procedure TestChunkArray_Add_And_Slide;
+
+        [Test]
+        procedure TestChunkArray_Copy_IsIndependent;
+
+        [Test]
+        procedure TestSeries_CreationAndIndexing;
+
+        [Test]
+        procedure TestSeries_Add_And_Copy;
+    end;
+
+implementation
+
+uses
+    System.Generics.Collections;
+
+{ TMyTestObject }
+
+function TMyTestObject.GenerateData(Count: Integer): TArray<Integer>;
+var
+    i: Integer;
+begin
+    SetLength(Result, Count);
+    for i := 0 to Count - 1 do
+        Result[i] := i;
+end;
+
+procedure TMyTestObject.TestChunkArray_Add_And_Slide;
+var
+    arr: TChunkArray<Integer>;
+    newData: TArray<Integer>;
+begin
+    // Test sliding with single additions
+    arr := TChunkArray<Integer>.CreateFromArray([], 5); // MaxCount = 5
+
+    arr.Add(10, 5); // arr = [10]
+    Assert.AreEqual(1, arr.Count);
+    Assert.AreEqual(10, arr[0]);
+
+    arr.Add(20, 5); // arr = [10, 20]
+    arr.Add(30, 5); // arr = [10, 20, 30]
+    arr.Add(40, 5); // arr = [10, 20, 30, 40]
+    arr.Add(50, 5); // arr = [10, 20, 30, 40, 50]
+    Assert.AreEqual(5, arr.Count);
+    Assert.AreEqual(10, arr[0]);
+    Assert.AreEqual(50, arr[4]);
+
+    // Now, slide the window
+    arr.Add(60, 5); // arr becomes [20, 30, 40, 50, 60]
+    Assert.AreEqual(5, arr.Count, 'Count should remain at MaxCount');
+    Assert.AreEqual(20, arr[0], 'First item should be slided out');
+    Assert.AreEqual(60, arr[4], 'Last item should be the new one');
+
+    // Test sliding with array addition
+    arr := TChunkArray<Integer>.CreateFromArray([1, 2, 3], 5); // arr = [1, 2, 3], MaxCount = 5
+    newData := [4, 5, 6, 7];
+    arr.Add(newData, 5); // arr becomes [3, 4, 5, 6, 7]
+    Assert.AreEqual(5, arr.Count, 'Count should be MaxCount after adding array');
+    Assert.AreEqual(3, arr[0]);
+    Assert.AreEqual(7, arr[4]);
+end;
+
+procedure TMyTestObject.TestChunkArray_Copy_IsIndependent;
+const
+    DATA_SIZE = 3000; // Approx 3 chunks
+    MAX_COUNT_COPY = 1500; // Partial copy
+var
+    original, fullCopy, partialCopy: TChunkArray<Integer>;
+    data: TArray<Integer>;
+    i: Integer;
+begin
+    data := GenerateData(DATA_SIZE);
+    original := TChunkArray<Integer>.CreateFromArray(data, -1);
+
+    // 1. Test full copy
+    fullCopy := original.Copy(-1);
+    Assert.AreEqual(original.Count, fullCopy.Count, 'Full copy count should match original');
+    for i := 0 to original.Count - 1 do
+        Assert.AreEqual(original[i], fullCopy[i], 'Full copy item should match original');
+
+    // 2. Test partial copy
+    partialCopy := original.Copy(MAX_COUNT_COPY);
+    Assert.AreEqual(MAX_COUNT_COPY, partialCopy.Count, 'Partial copy should have MaxCount items');
+    for i := 0 to partialCopy.Count - 1 do
+        // The partial copy contains the LAST items of the original
+        Assert.AreEqual(original[i + (DATA_SIZE - MAX_COUNT_COPY)], partialCopy[i], 'Partial copy item should match last part of original');
+
+    // 3. Test independence after modification
+    // Add an item to original. This modifies its last chunk.
+    original.Add(9999, -1);
+    Assert.AreEqual(DATA_SIZE + 1, original.Count, 'Original count should increment');
+
+    // Verify the full copy is unchanged.
+    Assert.AreEqual(DATA_SIZE, fullCopy.Count, 'Full copy count should NOT change');
+    Assert.AreNotEqual(9999, fullCopy[fullCopy.Count - 1], 'Last item of full copy should NOT be the new item');
+    Assert.AreEqual(data[DATA_SIZE - 1], fullCopy[fullCopy.Count - 1], 'Last item of full copy should be original last item');
+
+    // Verify the partial copy is unchanged.
+    Assert.AreEqual(MAX_COUNT_COPY, partialCopy.Count, 'Partial copy count should NOT change');
+end;
+
+procedure TMyTestObject.TestChunkArray_CreateFromArray(const DataSize, MaxCount: Integer);
+var
+    data, expectedData: TArray<Integer>;
+    arr: TChunkArray<Integer>;
+    effectiveCount: Integer;
+    i: Integer;
+begin
+    data := GenerateData(DataSize);
+    arr := TChunkArray<Integer>.CreateFromArray(data, MaxCount);
+
+    if (MaxCount < 0) or (MaxCount >= DataSize) then
+        effectiveCount := DataSize
+    else
+        effectiveCount := MaxCount;
+
+    Assert.AreEqual(effectiveCount, arr.Count, 'Count should match effective count');
+
+    if effectiveCount = 0 then
+        exit;
+
+    // We only expect the last 'effectiveCount' items from the original data
+    SetLength(expectedData, effectiveCount);
+    TArray.Copy<Integer>(data, expectedData, DataSize - effectiveCount, 0, effectiveCount);
+
+    for i := 0 to effectiveCount - 1 do
+        Assert.AreEqual(expectedData[i], arr.Items[i], 'Item at index should be correct');
+end;
+
+procedure TMyTestObject.TestSeries_Add_And_Copy;
+var
+    original, copy: TSeries<Integer>;
+begin
+    // 1. Create and add
+    original := TSeries<Integer>.CreateFromArray([1, 2, 3], 5); // Lookback = 5
+    Assert.AreEqual(Int64(3), original.TotalCount);
+
+    original.Add(4, 5); // Series: [4, 3, 2, 1]
+    original.Add(5, 5); // Series: [5, 4, 3, 2, 1]
+    Assert.AreEqual(5, original.Count, 'Count should be 5');
+    Assert.AreEqual(Int64(5), original.TotalCount, 'TotalCount should be 5');
+    Assert.AreEqual(5, original[0], 'Index 0 should be 5');
+
+    // 2. Test sliding
+    original.Add(6, 5); // Series: [6, 5, 4, 3, 2]
+    Assert.AreEqual(5, original.Count, 'Count should remain 5 after slide');
+    Assert.AreEqual(Int64(6), original.TotalCount, 'TotalCount should be 6');
+    Assert.AreEqual(6, original[0], 'Index 0 should be 6');
+    Assert.AreEqual(2, original[4], 'Last item should be 2');
+
+    // 3. Test copy
+    copy := original.Copy();
+    Assert.AreEqual(5, copy.Count, 'Copy count should match original count');
+    Assert.AreEqual(Int64(5), copy.TotalCount, 'Copy TotalCount should match its own count, not original TotalCount');
+    Assert.AreEqual(6, copy[0], 'Copy should have same data');
+
+    // 4. Test independence
+    original.Add(7, 5);
+    Assert.AreEqual(7, original[0], 'Original should be updated');
+    Assert.AreEqual(6, copy[0], 'Copy should NOT be updated');
+end;
+
+procedure TMyTestObject.TestSeries_CreationAndIndexing;
+var
+    series: TSeries<Integer>;
+    data: TArray<Integer>;
+begin
+    data := [10, 20, 30, 40, 50];
+    series := TSeries<Integer>.CreateFromArray(data, -1);
+
+    Assert.AreEqual(5, series.Count, 'Series count should be 5');
+    Assert.AreEqual(Int64(5), series.TotalCount, 'Series total count should be 5');
+
+    // Test reversed indexing
+    Assert.AreEqual(50, series[0], 'Index 0 should be the last element');
+    Assert.AreEqual(40, series[1], 'Index 1 should be the second to last element');
+    Assert.AreEqual(30, series[2]);
+    Assert.AreEqual(20, series[3]);
+    Assert.AreEqual(10, series[4], 'Last index should be the first element');
+end;
+
+initialization
+    TDUnitX.RegisterTestFixture(TMyTestObject);
+
+end.