When I finished Hungry Dog, I mentioned that an assembly version might be fast enough to move the message behind the image. I decided it was time to find out. Hungry Dog 2 takes the original BASIC idea and gives the background some much-needed speed.
Driving home, I happened to see a murmuration of starlings flying over the road. It was something I don't often see anymore in the suburbs. Coincidentally, I also ran across a Boids simulation. Inspired by both, I thought it would be fun to create something like it on the ZX81.
To pass the time, I’ve been creating pixel art on the ZX81 using a screen editor. One of the images, a hungry dog with a background message, became inspiration for a short animation program. Unlike most of my image programs, the text remains visible behind the dog, almost as though the image has a transparent background.
Looking for a challenge, I decided to rewrite Trap or Gold for the more primitive ZX80. Although similar to the ZX81, its original 4K ROM provided a much more limited version of BASIC. Not to be deterred, I set out to see how games might work on the ZX81’s older brother.
I’ve always liked programs that feel a little alive, even on a machine like the ZX81. For Heart Beat, as usual, I was inspired by others. I ran across this EKG Heart program by Holger Palmroth for the Spectrum and decided to adapt and expand it for the ZX81.
Today, I did a thing. I bought a 3D printer for the purpose of printing the badge for the Commodore 1541 disk drive. Yes, it is overkill, but I’ll use it later. I feel justified.
Sometimes a small ZX81 program can still feel like a magic trick. My latest program, MONO LISA, builds a simple picture of the Mona Lisa from a single encoded string using a compact run-length encoding (RLE) style routine. It is definitely slow, but that is part of the charm as you watch the image draw itself across the screen.
This week I received a new ZX81 book I purchased on eBay called "Timex Sinclair 1000 Programs, Games, and Graphics." A little graphic program in the back of the book inspired me to create a game called Lift. Can you catch the items before they fall? Let’s dig in.
When I first converted Wolf, Goat, Cabbage to the ZX81, I wanted to include an intro screen. Sadly, I didn’t get around to it at the time. This month, I finally circled back and it turned into quite the journey.
I was pursuing ideas for a simple role-playing or fighting game. The one I landed on was the concept of a single treasure chest. It fit the retro-computing theme perfectly. Trap or Gold is a simple game that doesn't need fancy graphics, speed, or memory — yet it’s still fun.