programextensions/scene/demos/voxels-chunk.xtl

Voxels, 1: a chunk is an array. 16 by 16 by 16 block numbers built from a height field in a few array expressions -- grass, dirt, stone, water below a level, sand at its shore, one tree -- then counted, cut and seen from above. (docs/voxels.md; the next demos draw it.) Run: just demo scene voxels-chunk (pictures go to work/draw/)