10 LET X = 10 // BALL               
20 LET Y = 3 // BALL                
30 LET U = - 1 //BALL SPEED                
40 LET V = 2 //BALL SPEED                
50 WAIT 20 
60 COLOR BLACK ,BLACK 
70 CURSOR X ,Y 
80 PRINT "_" ,
90 LET X = X + V 
100 LET Y = Y + U 
110 COLOR RED ,RED 
120 CURSOR X ,Y 
130 PRINT "_" ,
140 IF Y + U <= 1 THEN LET U = - U 
150 IF Y >= 24 THEN LET U = - U 
160 IF X + V <= 1 THEN LET V = - V 
170 IF X >= 40 THEN LET V = - V 
180 GOTO 50 
190