AMOSi:Limit Bob
an example can be found on AMOSPro_Examples:Examples/H-2/Help_28.AMOS
Restricts the visibility of a numbered Blitter OBject to the LIMITs of a rectangle on screen. You set up the size of this rectangle by simply entering its coordinates.
Bob 1,100,100,1
Limit Bob number,x1,y1 To x2,y2