Hi,   Sorry guys, I'm back again !   So, now I'm playing with the multi-sprite trick.... I successfully coded a stable 17 sprites display routine but I don't really understand how. I mean using "test and try", I finished to have a stable display (with a constant step between sprite, no overlapping...) but I don't understand why....     I look at the working timings but it doesn't make sense to me :   LDA #%00100011 ; missiles to 8 pixels + sprites close * 3 STA NUSIZ0 STA NUSIZ1