diff --git a/AuraTrader/MainForm.fmx b/AuraTrader/MainForm.fmx
index 59ab2b2..080fd1d 100644
--- a/AuraTrader/MainForm.fmx
+++ b/AuraTrader/MainForm.fmx
@@ -12,45 +12,45 @@ object Form1: TForm1
   DesignerMasterStyle = 0
   object MainPanel: TPanel
     Align = Client
-    Size.Width = 796.00000000000000000
-    Size.Height = 712.00000000000000000
+    Size.Width = 796.000000000000000000
+    Size.Height = 712.000000000000000000
     Size.PlatformDefault = False
     TabOrder = 2
     object Splitter1: TSplitter
       Align = Left
       Cursor = crHSplit
-      MinSize = 20.00000000000000000
-      Position.X = 169.00000000000000000
-      Size.Width = 8.00000000000000000
-      Size.Height = 712.00000000000000000
+      MinSize = 20.000000000000000000
+      Position.X = 169.000000000000000000
+      Size.Width = 8.000000000000000000
+      Size.Height = 712.000000000000000000
       Size.PlatformDefault = False
     end
     object WorkspacePanel: TPanel
       Align = Client
-      Size.Width = 619.00000000000000000
-      Size.Height = 712.00000000000000000
+      Size.Width = 619.000000000000000000
+      Size.Height = 712.000000000000000000
       Size.PlatformDefault = False
       TabOrder = 3
       object TabControl: TTabControl
         Align = Client
-        Size.Width = 619.00000000000000000
-        Size.Height = 672.00000000000000000
+        Size.Width = 619.000000000000000000
+        Size.Height = 672.000000000000000000
         Size.PlatformDefault = False
         TabIndex = 0
         TabOrder = 10
         TabPosition = PlatformDefault
       end
       object ToolBar: TToolBar
-        Size.Width = 619.00000000000000000
-        Size.Height = 40.00000000000000000
+        Size.Width = 619.000000000000000000
+        Size.Height = 40.000000000000000000
         Size.PlatformDefault = False
         TabOrder = 3
         object AddWorkspaceButton: TSpeedButton
           Action = AddWorkspaceAction
           Align = FitLeft
           ImageIndex = -1
-          Size.Width = 145.45458984375000000
-          Size.Height = 40.00000000000000000
+          Size.Width = 145.454589843750000000
+          Size.Height = 40.000000000000000000
           Size.PlatformDefault = False
           Text = 'Add'
           TextSettings.Trimming = None
@@ -59,20 +59,20 @@ object Form1: TForm1
           Action = TestAction
           Align = FitLeft
           ImageIndex = -1
-          Position.X = 145.45458984375000000
-          Size.Width = 145.45454406738280000
-          Size.Height = 40.00000000000000000
+          Position.X = 145.454589843750000000
+          Size.Width = 145.454544067382800000
+          Size.Height = 40.000000000000000000
           Size.PlatformDefault = False
           TextSettings.Trimming = None
           object TestPopup: TPopup
             PlacementTarget = TestButton
-            Size.Width = 400.00000000000000000
-            Size.Height = 400.00000000000000000
+            Size.Width = 400.000000000000000000
+            Size.Height = 400.000000000000000000
             Size.PlatformDefault = False
             TabOrder = 7
             object FlowLayout: TFlowLayout
-              Position.X = 224.00000000000000000
-              Position.Y = 167.00000000000000000
+              Position.X = 224.000000000000000000
+              Position.Y = 167.000000000000000000
               TabOrder = 4
               Justify = Left
               JustifyLastLine = Left
@@ -84,9 +84,9 @@ object Form1: TForm1
               end
               object LoadButton: TButton
                 Anchors = [akTop, akRight]
-                Position.Y = 19.00000000000000000
-                Size.Width = 47.00000000000000000
-                Size.Height = 22.00000000000000000
+                Position.Y = 19.000000000000000000
+                Size.Width = 47.000000000000000000
+                Size.Height = 22.000000000000000000
                 Size.PlatformDefault = False
                 TabOrder = 5
                 Text = 'Load'
@@ -95,7 +95,7 @@ object Form1: TForm1
               end
               object RandomButton: TButton
                 Anchors = [akTop, akRight]
-                Position.Y = 41.00000000000000000
+                Position.Y = 41.000000000000000000
                 TabOrder = 2
                 Text = 'Random'
                 TextSettings.Trimming = None
@@ -103,7 +103,7 @@ object Form1: TForm1
               end
               object StopButton: TButton
                 Anchors = [akTop, akRight]
-                Position.Y = 63.00000000000000000
+                Position.Y = 63.000000000000000000
                 TabOrder = 8
                 Text = 'StopButton'
                 TextSettings.Trimming = None
@@ -111,7 +111,7 @@ object Form1: TForm1
               end
               object ChartButton: TButton
                 Anchors = [akTop, akRight]
-                Position.Y = 85.00000000000000000
+                Position.Y = 85.000000000000000000
                 TabOrder = 7
                 Text = 'ChartButton'
                 TextSettings.Trimming = None
@@ -119,9 +119,9 @@ object Form1: TForm1
               end
               object SymbolsComboBox: TComboBox
                 Anchors = [akTop, akRight]
-                Position.Y = 107.00000000000000000
-                Size.Width = 177.00000000000000000
-                Size.Height = 22.00000000000000000
+                Position.Y = 107.000000000000000000
+                Size.Width = 177.000000000000000000
+                Size.Height = 22.000000000000000000
                 Size.PlatformDefault = False
                 TabOrder = 4
               end
@@ -130,9 +130,9 @@ object Form1: TForm1
         end
         object StrategyButton: TSpeedButton
           Align = FitLeft
-          Position.X = 290.90911865234370000
-          Size.Width = 145.45446777343750000
-          Size.Height = 40.00000000000000000
+          Position.X = 290.909118652343800000
+          Size.Width = 145.454467773437500000
+          Size.Height = 40.000000000000000000
           Size.PlatformDefault = False
           Text = 'Strategy'
           TextSettings.Trimming = None
@@ -142,14 +142,14 @@ object Form1: TForm1
     end
     object ObjectsPanel: TPanel
       Align = Left
-      Size.Width = 169.00000000000000000
-      Size.Height = 712.00000000000000000
+      Size.Width = 169.000000000000000000
+      Size.Height = 712.000000000000000000
       Size.PlatformDefault = False
       TabOrder = 4
       object ObjectsTabControl: TTabControl
         Align = Client
-        Size.Width = 169.00000000000000000
-        Size.Height = 712.00000000000000000
+        Size.Width = 169.000000000000000000
+        Size.Height = 712.000000000000000000
         Size.PlatformDefault = False
         TabIndex = 0
         TabOrder = 0
@@ -163,24 +163,24 @@ object Form1: TForm1
             end>
           TextSettings.Trimming = None
           IsSelected = True
-          Size.Width = 66.00000000000000000
-          Size.Height = 26.00000000000000000
+          Size.Width = 66.000000000000000000
+          Size.Height = 26.000000000000000000
           Size.PlatformDefault = False
           StyleLookup = ''
           TabOrder = 0
           Text = 'Modules'
-          ExplicitSize.cx = 66.00000000000000000
-          ExplicitSize.cy = 26.00000000000000000
+          ExplicitSize.cx = 66.000000000000000000
+          ExplicitSize.cy = 26.000000000000000000
           object TreeView: TTreeView
             Align = Client
-            Size.Width = 169.00000000000000000
-            Size.Height = 686.00000000000000000
+            Size.Width = 169.000000000000000000
+            Size.Height = 686.000000000000000000
             Size.PlatformDefault = False
             TabOrder = 0
             OnDblClick = TreeViewDblClick
             AllowDrag = True
-            Viewport.Width = 165.00000000000000000
-            Viewport.Height = 682.00000000000000000
+            Viewport.Width = 165.000000000000000000
+            Viewport.Height = 682.000000000000000000
           end
         end
       end
@@ -190,13 +190,13 @@ object Form1: TForm1
     Touch.InteractiveGestures = [Pan, LongTap, DoubleTap]
     DataDetectorTypes = []
     Align = Bottom
-    Position.Y = 712.00000000000000000
-    Size.Width = 796.00000000000000000
-    Size.Height = 128.00000000000000000
+    Position.Y = 712.000000000000000000
+    Size.Width = 796.000000000000000000
+    Size.Height = 128.000000000000000000
     Size.PlatformDefault = False
     TabOrder = 1
-    Viewport.Width = 792.00000000000000000
-    Viewport.Height = 124.00000000000000000
+    Viewport.Width = 792.000000000000000000
+    Viewport.Height = 124.000000000000000000
   end
   object ActionList: TActionList
     Left = 209
diff --git a/AuraTrader/MainForm.pas b/AuraTrader/MainForm.pas
index 2b60681..031f5a6 100644
--- a/AuraTrader/MainForm.pas
+++ b/AuraTrader/MainForm.pas
@@ -165,7 +165,7 @@ begin
     var chart := TMycChart.Create(Self);
     AlignControl( chart );
     chart.Height := Layout.ChildrenRect.Width*9/16;
-    chart.Lookback := 1000;
+    chart.Lookback.Value := 1000;
 
     /////
 
diff --git a/AuraTrader/Myc.Fmx.Chart.pas b/AuraTrader/Myc.Fmx.Chart.pas
index d1af204..af922cf 100644
--- a/AuraTrader/Myc.Fmx.Chart.pas
+++ b/AuraTrader/Myc.Fmx.Chart.pas
@@ -31,18 +31,19 @@ type
                 function GetCount: Int64; virtual; abstract;
                 function GetValueRange(StartIndex, Count: Int64; out Min, Max: Double): Boolean; virtual; abstract;
                 function Update: Boolean; virtual; abstract;
-                procedure Paint(const ACanvas: TCanvas; const AXForm, AYForm: TFunc<Double, Single>); virtual; abstract;
+                procedure Paint(const ACanvas: TCanvas; Lookback: Int64; const AXForm, AYForm: TFunc<Double, Single>); virtual; abstract;
+
+                property MainSeries: TSeries read GetMainSeries;
 
             public
                 constructor Create(AOwner: TMycChart);
                 property Count: Int64 read GetCount;
-                property MainSeries: TSeries read GetMainSeries;
                 property Owner: TMycChart read FOwner;
             end;
 
     private
         FSeriesList: TList<TSeries>;
-        FLookback: Integer;
+        FLookback: TWriteable<Int64>;
         FIdleSubscrId: TMessageSubscriptionId;
     protected
         procedure Paint; override;
@@ -66,8 +67,7 @@ type
             const ALineWidth: Single = 1.5
         );
 
-        // The maximum number of data points to display from the main series.
-        property Lookback: Integer read FLookback write FLookback;
+        property Lookback: TWriteable<Int64> read FLookback write FLookback;
     end;
 
 implementation
@@ -82,14 +82,14 @@ type
     TChartSeriesReceiver<T> = class(TMycProcessor<T>)
     strict private
         FCurrData: TMycDataArray<T>;
-        FLookback: Int64;
+        FLookback: TWriteable<Int64>;
     private
         FData: TWriteable<TMycDataArray<T>>;
     protected
         function ProcessData(const Value: T): Boolean; override;
         procedure Update; override;
     public
-        constructor Create(ALookback: Int64);
+        constructor Create(const ALookback: TWriteable<Int64>);
         function GetData(var Data: TMycDataArray<T>): Boolean;
         property Data: TWriteable<TMycDataArray<T>> read FData;
     end;
@@ -121,7 +121,7 @@ type
         FStyle: TCandleStyle;
     protected
         function GetValueRange(StartIndex, Count: Int64; out Min, Max: Double): Boolean; override;
-        procedure Paint(const ACanvas: TCanvas; const AXForm, AYForm: TFunc<Double, Single>); override;
+        procedure Paint(const ACanvas: TCanvas; Lookback: Int64; const AXForm, AYForm: TFunc<Double, Single>); override;
     public
         constructor Create(
             AOwner: TMycChart;
@@ -138,7 +138,7 @@ type
         FLineWidth: Single;
     protected
         function GetValueRange(StartIndex, Count: Int64; out Min, Max: Double): Boolean; override;
-        procedure Paint(const ACanvas: TCanvas; const AXForm, AYForm: TFunc<Double, Single>); override;
+        procedure Paint(const ACanvas: TCanvas; Lookback: Int64; const AXForm, AYForm: TFunc<Double, Single>); override;
     public
         constructor Create(
             AOwner: TMycChart;
@@ -169,7 +169,8 @@ constructor TMycChart.Create(AOwner: TComponent);
 begin
     inherited Create(AOwner);
     FSeriesList := TObjectList<TSeries>.Create(true);
-    FLookback := 10000;
+
+    FLookback := TWriteable<Int64>.CreateWriteable( 100 );
 
     FIdleSubscrId :=
         TMessageManager
@@ -231,8 +232,9 @@ var
 begin
     inherited;
     rect := Self.LocalRect;
+    var lookback := FLookback.Value;
 
-    if (FSeriesList.Count = 0) or (FLookback <= 1) then
+    if (FSeriesList.Count = 0) or (lookback <= 1) then
     begin
         Canvas.Fill.Color := TAlphaColors.Gray;
         Canvas.FillText(rect, 'No Data', false, 1, [], TTextAlign.Center, TTextAlign.Center);
@@ -243,7 +245,7 @@ begin
 
     for series in FSeriesList do
     begin
-        if series.GetValueRange(0, FLookback, seriesMin, seriesMax) then
+        if series.GetValueRange(0, lookback, seriesMin, seriesMax) then
         begin
             if not rangeInitialized then
             begin
@@ -269,7 +271,7 @@ begin
     if (globalMax - globalMin) = 0 then
         exit;
 
-    xTransform := function(index: Double): Single begin Result := rect.Right - (index / (FLookback - 1)) * rect.Width; end;
+    xTransform := function(index: Double): Single begin Result := rect.Right - (index / (lookback - 1)) * rect.Width; end;
 
     yTransform :=
         function(value: Double): Single begin Result := rect.Top + (1 - (value - globalMin) / (globalMax - globalMin)) * rect.Height; end;
@@ -280,7 +282,7 @@ begin
 
     for series in FSeriesList do
     begin
-        series.Paint(Self.Canvas, xTransform, yTransform);
+        series.Paint(Self.Canvas, lookback, xTransform, yTransform);
     end;
 end;
 
@@ -293,7 +295,7 @@ begin
     FDataSeries := TMycDataArray<T>.CreateEmpty;
     FData := FDataSeries;
     FDataProvider := ADataProvider;
-    FReceiver := TChartSeriesReceiver<T>.Create(AOwner.Lookback);
+    FReceiver := TChartSeriesReceiver<T>.Create(AOwner.FLookback);
     FReceiverTag := FDataProvider.Link(FReceiver);
 end;
 
@@ -347,7 +349,7 @@ begin
     Result := (Min <> MaxDouble);
 end;
 
-procedure TChartOhlcSeries.Paint(const ACanvas: TCanvas; const AXForm, AYForm: TFunc<Double, Single>);
+procedure TChartOhlcSeries.Paint(const ACanvas: TCanvas; Lookback: Int64; const AXForm, AYForm: TFunc<Double, Single>);
 var
     i, displayCount: Int64;
     x, candleWidth: Single;
@@ -355,7 +357,7 @@ var
     item: TDataPoint<TOhlcItem>;
     isUp: boolean;
 begin
-    displayCount := System.Math.Min(Data.Count, Owner.Lookback);
+    displayCount := System.Math.Min(Data.Count, Lookback);
     if displayCount <= 0 then
         Exit;
 
@@ -429,14 +431,14 @@ begin
     Result := (Min <> MaxDouble);
 end;
 
-procedure TChartLineSeries.Paint(const ACanvas: TCanvas; const AXForm, AYForm: TFunc<Double, Single>);
+procedure TChartLineSeries.Paint(const ACanvas: TCanvas; Lookback: Int64; const AXForm, AYForm: TFunc<Double, Single>);
 begin
     if not Assigned(MainSeries) or (Data.Count = 0) or (MainSeries.Count = 0) then
         Exit;
 
     var points := TPathData.Create;
 
-    var displayCount := System.Math.Min(Data.Count, Owner.Lookback);
+    var displayCount := System.Math.Min(Data.Count, Lookback);
     if displayCount < 2 then
         Exit;
 
@@ -460,7 +462,7 @@ end;
 
 { TChartSeriesReceiver<T> }
 
-constructor TChartSeriesReceiver<T>.Create(ALookback: Int64);
+constructor TChartSeriesReceiver<T>.Create(const ALookback: TWriteable<Int64>);
 begin
     inherited Create;
     FLookback := ALookback;
@@ -478,7 +480,7 @@ end;
 function TChartSeriesReceiver<T>.ProcessData(const Value: T): Boolean;
 begin
     Result := true;
-    FCurrData := FCurrData.Add(Value, FLookback);
+    FCurrData := FCurrData.Add(Value, FLookback.Value);
 end;
 
 procedure TChartSeriesReceiver<T>.Update;
diff --git a/Src/Myc.Core.Lazy.pas b/Src/Myc.Core.Lazy.pas
index 134ee95..aa297bf 100644
--- a/Src/Myc.Core.Lazy.pas
+++ b/Src/Myc.Core.Lazy.pas
@@ -5,6 +5,7 @@ interface
 uses
     System.Classes,
     System.SysUtils,
+    System.SyncObjs,
     Myc.Signals,
     Myc.Lazy;
 
@@ -81,13 +82,11 @@ type
     TMycProtectedMutable<T> = class(TInterfacedObject, TMutable<T>.IMutable, TWriteable<T>.IWriteable)
     private
         FWriteable: TWriteable<T>.IWriteable;
-        FLock: Integer;
+        FLock: TLightweightMREW;
     protected
         function Exchange(const Value: T): T;
         function GetChanged: TSignal;
         function GetValue: T;
-        procedure Lock; inline;
-        procedure Release; inline;
     public
         constructor Create(const AWriteable: TWriteable<T>.IWriteable);
         procedure SetValue(const Value: T);
@@ -243,11 +242,11 @@ end;
 
 function TMycProtectedMutable<T>.Exchange(const Value: T): T;
 begin
-    Lock;
+    FLock.BeginWrite;
     try
         Result := FWriteable.Exchange(Value);
     finally
-        Release;
+        FLock.EndWrite;
     end;
 end;
 
@@ -258,32 +257,21 @@ end;
 
 function TMycProtectedMutable<T>.GetValue: T;
 begin
-    Lock;
+    FLock.BeginRead;
     try
         Result := FWriteable.Value;
     finally
-        Release;
+        FLock.EndRead;
     end;
 end;
 
-procedure TMycProtectedMutable<T>.Lock;
-begin
-    while AtomicExchange(FLock, 1) = 1 do
-        YieldProcessor;
-end;
-
-procedure TMycProtectedMutable<T>.Release;
-begin
-    AtomicExchange(FLock, 0);
-end;
-
 procedure TMycProtectedMutable<T>.SetValue(const Value: T);
 begin
-    Lock;
+    FLock.BeginWrite;
     try
         FWriteable.SetValue(Value);
     finally
-        Release;
+        Flock.EndWrite;
     end;
 end;
 
diff --git a/Src/Myc.Lazy.pas b/Src/Myc.Lazy.pas
index 835814b..3a528b4 100644
--- a/Src/Myc.Lazy.pas
+++ b/Src/Myc.Lazy.pas
@@ -67,6 +67,8 @@ type
 
         function Protect: TWriteable<T>;
 
+        function AsMutable: TMutable<T>;
+
         property Value: T read GetValue write SetValue;
         property Changed: TSignal read GetChanged;
     end;
@@ -211,6 +213,11 @@ begin
     Assert(Assigned(FWriteable));
 end;
 
+function TWriteable<T>.AsMutable: TMutable<T>;
+begin
+    Result.Create(FWriteable);
+end;
+
 class function TWriteable<T>.CreateWriteable: TWriteable<T>;
 begin
     Result := CreateWriteable(Default(T));