The video shows a 512byte intro running on a ZX Spectrum. It was recorded from an emulator. "512byte" refers to the total length of the executable code that was used to create this effect. The effect was written entirely in Z80 assembler.
The intro is a remix of the signature for the V&A's Decode exhibition(1). Rather than basing my remix on their publicly available Processing code, I chose to completely recode the signature on the ZX Spectrum - the platform where I first began to explore digital art for myself.
You can download the original executable and source code from http://atebit.org/#decoderecode
Code, art and design - Paul "evilpaul" Grenfell