The watercourse supplying the waterfall (its aqueduct or leat) has the structure of three Penrose triangles.

The water falls off the edge of the aqueduct and over the waterwheel in an impossible infinite cycle; in his notes on the picture, Escher points out that some water must be periodically added to this perpetual motion machine to compensate for evaporation.

[2] The two support towers continue above the aqueduct and are topped by two compound polyhedra, revealing Escher's interest in mathematics as an artist.

The one on the right is a stellation of a rhombic dodecahedron (or a compound of three non-regular octahedra) and is known as Escher's solid.

This is a magnified view of a cluster of moss and lichen that Escher drew in ink as a study in 1942.