skulker = S = slack

slab [Apple]

1. n. A continuous horizontal line of pixels, all with the same color. 2. vi. To paint a slab on an output device. Apple's QuickDraw, like most other professional-level graphics systems, renders polygons and lines not with Bresenham's algorithm, but by calculating `slab points' for each scan line on the screen in succession, and then slabbing in the actual image pixels.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.