4K intro
A demo of at most 4096 bytes — all the graphics and music are computed on the fly.
A 4K intro is a demoscene classic: the whole program, graphics, music and effects included, fits in 4096 bytes. Nothing can be stored ready-made — everything is generated procedurally at runtime, and the code is squeezed through an executable packer on top.
The category lives on in compos at parties like Revision and Assembly, alongside the 64k intro and the 256-byte intro. On the PC, modern entries build the image in a GLSL shader and the sound in a softsynth such as 4klang. Pure sizecoding discipline, where every byte is negotiated.