mouseTrailExample :: (StartStop t) => EvStream t Float -> EvStream t [Event] -> Behavior t (Reactive t Picture)
mouseTrailExample clock ev = do
  bMousePos <- holdEs (0,0) (filterMap (\xs -> case filterMap isMouseChange xs of
                                      [] -> Nothing
                                      (x:_) -> Just x) ev)
  bTrail <- holdLastNSecs 1.2 clock bMousePos

  return $ fmap decayColorLine bTrail
mouseTrailExample :: (StartStop t) => EvStream t Float -> EvStream t [Event] -> Behavior t (Reactive t Picture)
mouseTrailExample clock ev = do
  bMousePos <- holdEs (0,0) (filterMap (\xs -> case filterMap isMouseChange xs of
                                      [] -> Nothing
                                      (x:_) -> Just x) ev)
  bTrail <- holdLastNSecs 1.2 clock bMousePos

  return $ fmap decayColorLine bTrail
mouseTrailExample clock ev = do
  bMousePos <- holdEs (0,0) (filterMap (\xs -> case filterMap isMouseChange xs of
                                      [] -> Nothing
                                      (x:_) -> Just x) ev)
  bTrail <- holdLastNSecs 1.2 clock bMousePos

  return $ fmap decayColorLine bTrail