Cubes flying at different fractions of light speed. Length contraction plus light delay make each cube look rotated — the Terrell–Penrose effect.
James Terrell & Roger Penrose, 1959
A cube moving near light speed is length-contracted, but light from its trailing face left earlier. The two effects together look like a rotation — Terrell and Penrose both published it in 1959. Each cube here has a different β; motion lets the fast ones lap the rest.
isometric
BoostAt rest, a cube. Near c, light delay shears it — the same cube, apparently rotated.