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Geometric Model by R. L. Curtis, a Student of A. Harry Wheeler, One-Sided Polyhedron

Geometric Model by R. L. Curtis, a Student of A. Harry Wheeler, One-Sided Polyhedron

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This tan paper model has an equilateral triangle for a base and three triangles on the sides that meet in a point. A thin pyramid with a quadrilateral base is attached to each side edge of this larger triangular pyramid. One edge of each thin pyramids coincides with an edge of the larger triangular pyramid. One short edges from each pyramid meets another thin pyramid at the top of the model. Many sides are coplanar. A tag on the side reads: 650.
According to Wheeler’s catalog, model 650 has six vertices, fifteen faces, fifteen edges, and ten faces, for e - k +f = 1. Model 651 has ten vertices (e=10), eighteen edges (k=18), and nine faces, (f = 9) for an Euler characteristic of e – k + f = 1. Compare MA.304723.378 (which has a tag that reads 650 but is not the same shape as this model) and 304723.377 (which has the same shape as this model but is numbered 651).
A. H. Wheeler, "List of Models," Mathematics Collections, Non-accession number 1979.3002.83, NMAH.
Currently not on view
Object Name
Geometric Model
date made
1938 10 30
Wheeler, Albert Harry
Curtis, Robert L.
place made
United States: Massachusetts, Worcester
Physical Description
paper (overall material)
tan (overall color)
cut and glued (overall production method/technique)
average spatial: 11 cm x 17.5 cm x 14.3 cm; 4 11/32 in x 6 7/8 in x 5 5/8 in
ID Number
accession number
catalog number
Credit Line
Gift of Helen M. Wheeler
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
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