[
  {"op": "doc", "text": "an UNNAMED reusable SMA smoother over open input role z; defaults to graph"},
  {"op": "input", "role": "z"},
  {"op": "add", "type": "SMA", "name": "sma"},
  {"op": "feed", "role": "z", "into": ["sma.series"]},
  {"op": "expose", "from": "sma.value", "as": "smoothed"}
]