A second voice, not a second system. Sketch marks are drawn free-hand rather than on a compass, but they are built to the interface icons' own rules: 24×24, round caps, one currentColor stroke, sized only from --dt-size-icon-*. They read at the same weight at every step because they share the same box.

They are not interface icons. A button or a nav item still takes a library glyph. A hand-drawn line in a toolbar reads as a mistake. A sketch mark belongs where the page is speaking in its own voice: an empty state, a callout, a marketing accent. Six ship with the system in system/assets/icons/sketch/: sun, leaf, spark, heart, wave, loop.