I recently got back into retro hardware. My starting point was gaming, as I ordered one of the new Atari 7800s that plays the old cartridges. In my haste to grab a few games, I inadvertently purchased a complete 2600 with controllers. I’ll blame travel and lack of sleep for missing that detail. But it gave me the opportunity to attempt something I’ve never done before: restore the controllers.
Every once in a while, a small, silly idea turns into a surprisingly fun little project. That’s exactly what happened with my latest ZX81 experiment, a reaction-based game inspired by the old nursery rhyme: Duck, Duck, Goose.
Lately I’ve been on a binge — a retro computing hardware binge. It started last year when I went searching for a working Timex Sinclair 1000. The idea was simple. Set it up and run my own programs on real hardware again. What began as a hunt for one machine quickly turned into something bigger.
I’d been thinking about writing a better clock program for the ZX81 for some time but never acted on it. That is, until yesterday when I saw a flip-style digital clock program on the C64. The result is a sort of digital flip clock program for the ZX81 that ended up being quite a fun journey.
I thought I’d try something a bit different this month. I’d been looking at different ways to build maps for years but never really did much with them. After watching a video on binary partitioning, I decided to see if I could build a simple map builder on the ZX81.
This is the result.
I wrote this back in August and I’m finally getting around to publishing it. It was first shared in my BASIC group, but the ZX81 lacks a lot of the functionality needed for it to run well. Undeterred, I hacked at the program to not only display the twisted cylinder, but also add a bit of randomness to the demo.
I’d seen a few different BASIC programs that print out a map of the world. Generally blocky, they still looked decent, but much of the data was too big for the ZX81—until I ran across a C64 version based on a Spectrum program. Examples in hand, I built a version for the ZX81.
Having finished my last Truchet tiles program in BASIC, I wondered how fast it would run in machine code. Soon afterward, I gave it a try, writing a version that runs significantly faster than the BASIC one. Let’s dive in and see how it works.
Sometimes ideas drop right into your lap. In the case of this month’s program, it was a mix of a post and a video that led me to this Truchet animation. A simple concept, but it worked way better on the ZX81 than I expected.
It’s funny how a random video can spark an idea. One moment I’m watching someone play around with ASCII art, and the next I’m thinking, “Hey, I could make something like that on the ZX81.” That little spark turned into a weekend project: a simple banner program using different fonts. How fun!