1 X=800:Y=800:X1=10:G=0
3 CLS
4 PSET X/100,Y/100,1
8 IF SW AND 1 THEN G=G-1 ELSE G=G+1
9 IF SW AND 8 THEN X1=X1+1
10 IF SW AND 4 THEN X1=X1-1
11 X=X+X1:Y=Y+G
12 IF X<0 THEN X=0:X1=-X1
13 IF X>3100 THEN X=3100:X1=-X1
14 IF Y>1500 THEN Y=1500:G=-G
15 GOTO 3
