I need to add the value of x, (delta)x, and xmin. how do i go about that? also, can i cp (NUMBERONE)? Or do I need to ld a,(NUMBERONE) / cp b? Also, when I sub c, which variables am i subtracting? c from a, stored into a, or a from c stored into a? Last thing. I saw how to do a PxON, now how do I test a pixel, and do a PxOff? Thanks Glen