+race between cdu off (due to watchdog or short) and points
+
+
layout polarity diagram colourful segment encoding:
- abstract away the pixel encoding scheme, at least somewhat
- implement segmap so that we can do midx
- decide what to do about crossings (difficult to show both tracks)
- wire layout diagram thing into Tcl and see speed etc.
make moveable feature selection in subseg2display bitwise rather than
setwise
-1. Write lots and lots and lots of PIC programs
+safety system no crashes at crossovers please