I came to kinetic Monte Carlo while studying how nucleosomes are arranged in budding yeast. Nucleosomes are proteins around which DNA is wrapped in eukaryotic cells (think the “spindle” in a “spool of (DNA) thread”). Experimental assays of nucleosomes show ordered arrays near boundaries: a nucleosome-free region, a transcription-factor site, or the edge of a gene can act as a landmark, and the average positions of the next few nucleosomes oscillate away from it. The pattern is striking enough to invite a tempting question: are the nucleosomes individually programmed to those positions, or can much of the order emerge from particles packing against a boundary?

Osmos is a game about being a blob in a void full of other blobs. Absorb something smaller and you grow; touch something larger and it eats you. You move by ejecting part of yourself in the opposite direction, which means every course correction makes you smaller. It is a beautiful game built on one rule of physics.

My friend Ryan Miller sent me an Excel spreadsheet with a game he’d invented called Territories. It had the satisfying quality of a good pencil-and-paper game: the rules fit in a sentence, but the strategy is unclear. It feels like a simplified Go.