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"The pyramid of the first order is a form consisting of eight isoceles triangular faces, each of which interesects all three crystallographic axes, the intercepts upon the two horizontal axes being equal." — Ford, 1912

First order pyramid

"The pyramid of the first order is a form consisting of eight isoceles triangular faces, each of which…

"The tetrahexahedron is a form composed of twenty-four isoceles triangular faces, each of which intersects one axis at unity, the second at some multiple, and is parallel to the third." — Ford, 1912

Tetrahexahedron

"The tetrahexahedron is a form composed of twenty-four isoceles triangular faces, each of which intersects…