#155Isoline Topographic Layer

A rolling fbm terrain (sourceA) — water, grass, sand, rock and snow banded by height — overlaid with topographic contour lines that reveal a neon cyan/magenta layer (sourceB) only along the isolines. iso = abs(fract(h*N + scroll) - 0.5); mask = smoothstep(w, 0, iso) keys B onto the contours while the rest stays terrain. The level count N breathes and the elevation offset scrolls so the contours creep uphill; every fifth line is drawn heavier as an index contour. The neon lines bloom, giving a live topographic-map composite with no pointer.