Poly Banana

Low-poly art builds a shape from a small number of flat triangles, each filled with one shade. The eye fills in the curvature from the changes in shade between neighbouring facets, so a few dozen triangles are enough to suggest a smooth, rounded object. The style comes from early real-time 3D graphics, where every polygon had a cost, and is now a common choice in illustration and games.

This banana is 63 triangles, drawn as three meshes: a bright yellow, a slightly darker yellow for the middle band, and brown for the ends of the stem and the tip. The triangles do not share any corners and do not make a closed solid. Each one sits at its own depth in z, tilted by its own amount. Seen straight down the z-axis with an orthographic camera, the triangles fit edge to edge into a flat banana, and because each triangle faces a slightly different direction, each one catches a different amount of light. Turn the view away from the z-axis and the banana breaks apart into a cloud of scattered triangles.

After a Desmos graph by @aple314.