ShadowArc Solar Desk: A Gnomonics Workshop

Why it surfaced

ShadowArc recomputes gnomon angles and hour lines from latitude, then lets users place a nodus on a polar board and export a PNG. It also includes an 80-plus-city atlas, recognition drills, and an unusually candid warning that its geometry is for STEM learning and backyard builds—not certified surveying.

An offline Android workshop for designing and learning about horizontal, vertical-south, and equatorial sundials.