There are several attractive polyhedron compounds consisting of three cubes. The first (left figures) arises by joining three cubes
such that each shares two axes (Holden 1991, p. 35; right figure). In other words,
it consists of three cubes, each rotated by 1/8 of a turn about the line joining
the centroids of opposite faces. A second (middle figures) rotates two cubes about
a axis by 1/8 of a turn relative to
one another, producing a dodecagrammic prism (middle figures). A third compound (right
figure) can be constructed by rotating two cubes about a axis with respect to each other.

These compounds will be implemented in a future version of the Wolfram Language as PolyhedronData["CubeThreeCompound",
n]
for ,
2, 3.

The first compound is depicted atop the left pedestal in M. C. Escher's
woodcut Waterfall (Bool et al. 1982, p. 323).

For the first compound, the common solid is a chamfered cube while the convex hull is a truncated octahedra
with non-regular hexagonal faces. For the second, the common solid and convex
hull are dodecahedral prisms. For the third, the common solid is a 9-trapezohedron
and the convex hull is a gyroelongated nonagonal dipyramid.

The Escher compound divides the three component cubes into 67 individual cells (Hoeflin 1985). Whether another configuration of three intersecting cubes can yield more cells is an unsolved problem.

Escher's 3-cube compound can be constructed to produce cubes with unit edge lengths using pieces as illustrated above, where