DOC

pointlist:
word	points in list
word	-
dword	x,y,z
...

projectedpointlist:
word	points in list
word	-
.
word	sx	0
word	sy	2
word	fl	4
word	-	6
dword	z	8
word	x	12 ;these could overflow :-( since the actual ones are 32 bits
word	y	14 ;-"-

polygroup:
word sides (0=end)
word color 
word x,y
...

edgelist:
word edges
word -
.
word v1,v2,f,0 	f&8000:hidden edge

hline list:
word starty
...
word x1(-32767=end),x2