For March's program of the month, I drew inspiration from one of my older demos, The Ball. Like many young kids from the early eighties using BASIC, I took a stab at animating a bouncing ball. It is a a relatively easy program to write depending on how complex you want to make the math. In my case, it is very simple math, no physics involved here. I wanted something a little more interesting, however, and decided to add curtains. As the ball moves behind them them it changes colors. The Ball is still a very slow demo though, so in 2012 I sped it up by compiling it with MCODER II. This months program is based on both versions, merged together to show you the difference between them. The Ball Redux combines a little old with a little new, but at its core is still my original program.
Head on over to my ZX81 site to catch up on past programs of the month.