More of a simulation, this program is more fun with other play.

As a young teenager, I often wrote programs that I would integrate into other play. In this case, I had probably watched War Games again. The idea of a computer talking to you made for some fun fantasy play. Comp Control a little pretend play where my lowly ZX81 mimicked a much more sophisticated world. I’m sure I was running around my room thinking up some crazy way to save the world.

As a stand along program, it is pretty basic. You have to type in the password-something I simplified and shared so you don’t have to guess it. The…


A refinement of my earlier picture scene adding in movement using a double buffer.

I was hoping to have finished Gem Quest by now, but May didn’t afford much time. With Summer arriving and the pandemic seeming to be winding down, at least in Boise, my attention is elsewhere. With a short list of ideas, I decided to play off last month’s theme. Picture in Motion isn’t new, but it is more interesting to watch.

Not straying too far, I decided to work on something that would’t take me too long to complete. I wanted to try my hand at animating the line drawing. Time kept me from getting too grandiose. …


The Picture Asm is my try at converting an old BASIC program to z80 assembler.

When Simeon Dwyer shared his machine language line drawing routine, I immediately thought of redoing “The Picture.” Most of my z80 assembly has been with my Gem Quest game. I decided it would be a nice diversion to work on something else, even if a quick one. Picture Asm is the result of that diversion.

Before getting started, I had to convert Simeon’s existing assembly into something I could use. JZeddy doesn’t like capitals, so I lower cased the entire program. …


My original idea for a ZX81 version of Ultima in BASIC.

I’ve talked about ZX-Ultima before. It was first attempt at building an Ultima like game on the ZX81 using BASIC. Written in 2012, it was a pretty ambitious project for me. I really enjoyed playing Ultima III on my C64 as a teenager. I always wondered what it would look like on my ZX81. It was bad. Yet, at the same time you could see the seeds of what would come later.

Writing a ZX81 Ultima game was always going to be a challenge. I mean, the ZX81 uses it’s z80 processor to display the screen. Right off the bat…


Capturing my progress in developing Gem Quest in images and movies on Flickr.

If you’ve been following me the last couple of months, you know I’ve been revisiting Gem Quest. Intended to be an Ultima style game for the ZX81, outside of a few demo’s I really hadn’t gotten far. That isn’t the case now. I’ve spent the last month learning z80 assembly code and hacking my way through the game. Tracking my progress, I’ve been capturing that journey in pictures and movies, which I’ve uploaded into a Flickr album.

A good part of my early journey was learning z80 assembler and finding a way to compile it. I ended up landing on…


Three years later, I attempted to build Gem Quest again, but didn’t progress much further.

After sharing Tiles, I started to dig into my previous attempts at building an adventure game. Digging through my past research, I thought about encoding the world differently. Sadly, my experiments using MCODER failed. This spurred me to try assembler again and, to my surprise, build a good start to my game. But first, a trip down memory lane and review my first attempt at building Gem Quest.

After finishing Tiles in 2013, I started research on what the game would be about. Liking the idea of stones or gems, I researched different gemology sites and legends. I found the…


This is my an attempt to emulate an Ultima style game. Tiles is a working prototype of the tiles based graphics engine.

In 2012 I wanted to see if I could make an Ultima style game on the ZX81. I had an ambitious plan centered on the tile based graphics. After a few months of testing, I was able to create a working prototype called Tiles. Although the game isn’t done, the idea behind it shows promise. You can move around the map using the standard ASDW movements. Other commands are placeholders for what could be. This article explores how Tiles came to be.

When my parents bought me a used C64, one of the first games I played was Ultima III


A simple graphic animation that draws the Ocean Pacific logo from eighties.

As 2020 wound down, I had a couple of different ideas for new ZX81 programs. Most of them were graphic programs of various sorts. Themes ranged from dumpster fire pictures, an advent calendar, a virus action game, to a solo RPG. Although they were all great ideas, I didn’t think I’d get any complete enough to publish. In the end, I decided to enter in one of my old graphic programs of the Ocean Pacific logo.

Running the program, I it will bore you quickly watching it draw the O and top of the P. Although the ZX81 had great…


Here is my 1628 Santa with Reindeer and Sleigh, freshly built in Mecabricks and rendered with Blender.

Tis the season to render Santa. Well that wasn’t really my plan, but it worked out that way. I was browsing around Bricklinks, mostly trying to update some of the recent sets. Searching for a small reindeer figure, I ran across LEGO set 1628 Santa with Reindeer and Sleigh. A great set from 1989, it looked like it would be a fun set to render.

I’ve been pretty busy in 2020, building quite a few renders. Most were of small sets, but there are a few big ones as well. Sadly, I didn’t get around to putting many on my…


Enter in a title, some data, and you can create a simple bar chart on your ZX81.

As usual, I procrastinated a bit in finishing my ZX81 program for November. Between holidays, work, and NaNoWriMo, I didn’t get around to it until this last weekend. I decided to try something a little different for this month’s program. The program itself, Charts, is a simple line graph plotter-spelling and bugs galore. As interesting as that program is, the real story is how I entered it.

Coming out of my failure last month, I decided to shortcut the whole ordeal this month. After digging through my programs, I decided on a program with limited graphics. This was on purpose…

Steven Reid

Computer dude, amateur photographer, artist, author. Read my blog at https://www.reids4fun.com.

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