The Elongated Square Cupola

The elongated square cupola is the 18th Johnson solid (J19). It has 20 vertices and 18 faces (4 equilateral triangles, 13 squares, and 1 octagon).

The elongated square

The elongated square cupola can be constructed by attaching an octagonal prism to a square cupola (J4), lengthening it; hence the name elongated.

It can also be considered as a diminishing of the rhombi­cubocta­hedron: the result of cutting off a square cupola from the latter.


Here are some views of the elongated square cupola from various angles:

Projection Envelope Description
Regular octagon

Top view.


Front view.


22.5° side view.


The Cartesian coordinates of the elongated square cupola with edge length 2 are:

These coordinates are obtained by deleting 4 vertices from the rhombicuboctahedron.

Last updated 11 Apr 2018.

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