Elongated dipyramid

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Set of elongated dipyramids
Faces	2n triangles, n squares
Edges	5n
Vertices	2n+2
Symmetry group	Dnh
Dual polyhedron	bifrustums
Properties	convex

In geometry, the elongated dipyramids are an infinite set of polyhedra, constructed by elongating an n'-agonal bipyramid (by inserting an n-agonal prism between its congruent halves.

There are three elongated dipyramids that are Johnson solids made from regular triangles and squares. Higher forms can be constructed with isosceles triangles.

[edit] Forms

• Elongated triangular dipyramid (J14) - 6 triangles, 3 squares - dual Triangular bifrustum
• Elongated square dipyramid (J15) - 8 triangles, 4 squares - 8 dual Square bifrustum
• Elongated pentagonal dipyramid (J16) - 10 triangles, 5 squares - dual Pentagonal bifrustum
• Elongated hexagonal dipyramid - 12 triangles, 6 squares - dual Hexagonal bifrustum
• ...
• n-agonal elongated dipyramid - 2n triangles, n squares - duals bifrustums