I started this, but ran into a roadblock. How do I place sprites randomly in an off-screen area?

The following program will place 64 sprites randomly on the screen. Could you refer to it? ACLS FOR I=0 TO 63:SPSET I,I:NEXT I FOR I=0 TO 63 'RND(N) yields random number from 0 to N-1. X=RND(400):Y=RND(240) SPOFS I,X,Y NEXT I WHILE TRUE:VSYNC 1:WEND