ClrHome
Input "BEGIN=", B
Input "END"=, E
Input "PARTS=", N

(E-B)/N->W
0->S

B+W->X
Lbl Z
Y1->H
S+W*H->S
X+W->X
If X<=(E-W)
Goto Z

B->X
S+W*Y1->L
E->X
S+W*Y1->R
Disp "LEFT:RIGHT:TRAP=",L,R,(L+R)/2

0->X
0->S
Lbl V
WY1(WX+B+W/2)->H
S+H->S
X+1->X
If (X<=(N-1))
Goto V

Disp "MID=",S