| 词条 | Hexagonal bifrustum | ||||||||||||||||||
| 释义 |
The hexagonal bifrustum or truncated hexagonal bipyramid is the fourth in an infinite series of bifrustum polyhedra. It has 12 trapezoid and 2 hexagonal faces. This polyhedron can be constructed by taking a hexagonal dipyramid and truncating the polar axis vertices, making it into two end-to-end frustums. Several types of crystal take this shape.[1] It has also been used in the design of 14-sided dice, which may be used to generate randomly chosen playing cards.[2] It also has application in novelty promotional calendars: one month can appear on each of the trapezoids, and an advertising or other message on each of the hexagons.{{citation needed|date = January 2017}} References1. ^{{citation|title=Equilibrium forms of very small metallic crystals|first=W.|last=Romanowski|doi=10.1016/0039-6028(69)90180-0|journal=Surface Science|volume=18|issue=2|date=December 1969|pages=373–388}}. 2. ^Set of five, fourteen sided poker dice, Patent US 8074986 B1, Douglas A. Gebhart, filed September 30, 2008. External links
1 : Polyhedra |
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