Mine

x = 10
y = 10
r = 20
c = 9
xvel = 10
yvel = 20

x1 = 1
y1 = 1

screenx=640
screeny=480
page1 = 0
page2 = 1

xdir = 1
ydir = 1
SCREEN 18,,2
a$ = inkey$
WHILE NOT a$ = "q"
    IF x1 < 1 THEN:x1 = 1:ENDIF
    IF y1 < 1 THEN:y1 = 1:ENDIF
    screenset page1,page2
    GETMOUSE xvel,yvel
   
    a$ = inkey$
    x = x + (xvel * xdir)
    y = y + (yvel * ydir)
    IF x > screenx - r THEN
        xdir = -xdir
        x = screenx - r
    ELSEIF x < r THEN 
        x = r
        xdir = -xdir
    ENDIF
    IF y > screeny - r THEN
        ydir = -ydir
        y = screeny - r
    ELSEIF y < r THEN
        y = r
        ydir = -ydir
    ENDIF

    GOSUB drawball
WEND
END
drawball:
CLS
GOSUB printstuff
CIRCLE (x,y),r,c,,,,F
sleep 20
screencopy
RETURN

printstuff:
LOCATE 2,4
PRINT "Xvel: "; xvel
LOCATE 3,4
PRINT "Yvel: "; yvel
LOCATE 4,4
PRINT "X: "; x
LOCATE 5,4
PRINT "Y: "; y

LOCATE 6,4
PRINT "mousex: "; x1
LOCATE 7,4
PRINT "mousey: "; y1

LOCATE 29,2
PRINT "Press 'q' key to exit"
RETURN