This book explores computation, specifically the craft of writing computer code, as a medium for drawing. Exercises, essays, algorithms, diagrams, and drawings are woven together to offer instruction, insight, and theories that are valuable to practicing architects, artists, and scholars. This book can serve as a primer for those new to programming or motivation and context for those with experience. "Computing" and "drawing" are both deeply historical and loaded terms. Although digital media is often positioned in opposition to the "manual" act of drawing, the broader territory of "computing" includes matters of language, rules, procedures, and orders that are very much compatible with the presence of ink on paper. Indeed, the nature of drawing--a temporal medium governed by marks that can be precisely defined, but not easily edited--provides welcome structure for computational methods.