A drawing system of outline marks, nine-pixel labels and leader rules for monochrome layouts. Every code on this sheet names a real part of it.
Nine marks carry the whole system. Each is drawn on a 24-unit grid at one-pixel stroke, so it holds its weight at any size.
Marks never sit alone. They group into clusters of four to six parts, aligned to a single edge.
Scale does the work an accent colour usually does. The gap between 9px and 132px is the only contrast this sheet needs.