!half_window   /rewritten 2/17/94/***VL/
! a, b, resolution
shadow on
resol c
muly b
mulx a/2
j=a/2
Pen F_
cprism_ G_,H_,I_,
8,C_,
-1,0,8,
-1,1,8,
1,1,8,
1,0,13+64,
0,0,900,
0,180,4013+64,
-1,0,15,
1,0,15

end