Here is my only Atari 2600 demo I’ve ever wrote. It’s a 3D Copper bar demo that I adapted for the 2600 from a GBA demo. I’m actually using the exact same effect as the GBA demo on the 2600. Of course, the 2600 is a bit more challenging since you have 128 bytes of RAM and enough video RAM to hold half a scanline (I’m not kidding here… half a scanline). Sorry about the filename — it needs to be renamed when downloading since WordPress.com doesn’t seem to allow .asm as a file extension when uploading.