A->Z
S->M
If Z=0
-0.000001->Z
If M=0
-0.000001->M
Y1(M)->G
Z->H

If not(real(M)) or not(real(G)) or not(real(H))
Return

prgmROT3D

2NE/(R-L)->M
2NQ/(T-B)->G
-(F+N)W/(F-N)-2FN/(F-N)->H

If H<=0
Return

-10M/H->U
-10G/H->V

P->Z
O->M
If Z=0
0.000001->Z
If M=0
0.000001->M
Y1(M)->G
Z->H
If not(real(M)) or not(real(G)) or not(real(H))
Return

prgmRot3D
2NE/(R-L)->M
2NQ/(T-B)->G
-(F+N)W/(F-N)-2FN/(F-N)->H

if H<=0
Return

-10M/H->X
-10G/H->Y

Line(X,Y,U,V)