# Square dipyramid (EntityTopic, 16)

A square dipyramid is a special case of the pyramid where the base is a square pyramid. It is also a special case of the dipyramid where the base is a square.

## Equations

• Variables:
l ⇒ length of each line in the square dipyramid
total edge length = 13l
total surface area = (1 + 6√3) · l2
surcell volume = 2√23 · l3
bulk = Unknown
[!x,!y] ⇒ triangular prism
[!z,!w] ⇒ square pyramid

## Net

The net of a square dipyramid is two square pyramids attached at their bases with four tetrahedra each attached to another face of one of the square based pyramids.

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## Projection

The parallel projection of a square dipyramid is the following: Notable Tetrashapes Regular: pyrochoron • aerochoron • geochoron • xylochoron • hydrochoron • cosmochoron Powertopes: triangular octagoltriate • square octagoltriate • hexagonal octagoltriate • octagonal octagoltriate Circular: glome • cubinder • duocylinder • spherinder • sphone • cylindrone • dicone • coninder Torii: tiger • torisphere • spheritorus • torinder • ditorus

 22. 22Dicone 23. 2Square dipyramid 24. 121Coninder List of tapertopes