For example GET/PUT had this one:
SCREEN 1
DIM Box%(1 TO 200)
x1% = 0: x2% = 10: y1% = 0: y2% = 10
LINE (x1%, y1%)-(x2%, y2%), 2, BF
GET (x1%, y1%)-(x2%, y2%), Box%
DO
PUT (x1%, y1%), Box%, XOR
x1% = RND * 300
y1% = RND * 180
PUT (x1%, y1%), Box%
LOOP WHILE INKEY$ = ""