This appendix will only be written if time allows ...
Just one note: If one wants to control the size of the Render window, and thus the images that comes out of WriteImg, one should look in the map file, with the place shown below, and know that the two numbers are 64 larger than the image size! In this case, we get 448 by 448. Know, that dmconvert requires images to be a multiple of 16 to make MPEGs.
(@5 =cxNRPanel [1] { (title "Render") (maxiSize =cxWidgetSize { (width 512) (height 512) } )