Pyrochlor lattice

Periodic structure known from the pyrochlore crystal structure in solid state physics (network of corner-sharing tetrahedra). In these crystal systems ions reside on the corners of tetrahedra and experience magnetic exchange with each other (see https://en.wikipedia.org/wiki/Spin_ice)

Here, a subset of tetrahedra is carved from the lattice that beautifully forms a tetrahedron itself.

Not easy to print due to a large number of overhangs and bridges. Finally managed using PLA and about 0.2mm