64k intro
A demo compo class where the whole production — code, music and graphics — must fit in 65536 bytes, forcing everything to be generated procedurally at runtime.
A 64k intro may weigh exactly 65,536 bytes as a finished executable. Since a single texture or audio file is already bigger than that, nothing can be stored ready-made: geometry is built mathematically, textures are computed, and sound is played by a softsynth fed notes rather than samples. The result is squeezed with dedicated packers such as kkrunchy. The class has had its own categories at the major demoparties since the 1990s.
The smaller sibling class, 4k, presses the same idea into 4096 bytes, and edge cases like the game .kkrieger (96k) showed how far procedural generation can carry. The point isn't thrift for its own sake but the elegance it forces: when every byte counts, maths is cheaper than data.