#### 7.2.123 stereowin

`(stereowin CAM-ID [no|horizontal|vertical|colored] [gapsize])`
  Configure CAM-ID as a stereo window. no: entire window is a single pane, stereo disabled
  horizontal: split left/right: left is stereo eye#0, right is #1.
  vertical: split top/bottom: bottom is eye#0, top is #1.
  colored: panes overlap, red is stereo eye#0, cyan is #1.

  A gap of `gapsize` pixels is left between subwindows; if omitted, subwindows are adjacent. If both layout and gapsize are omitted, e.g. (stereowin CAM-ID), returns current settings as a `(stereowin ...)` command list. This command doesn't set stereo projection; use `merge camera` or `camera` to set the stereyes transforms, and `merge window` or `window` to set the pixel aspect ratio & window position if needed.