How to teach paper-folding and cutting: a practical manual-training aid (1892)
[Litchfield, Norma MacLeod] [from old catalog] · Lebanon, Ohio, March brothers · leaf 94
K<gNo /J/ —a cube connecting two square pyramids. A solidwhich has eight equal faces, each face an equilateraltriangle, is called an octahedron. Such a solid isrepresented in figure No. 129, and the plan is shownin the next figure. Eight equilateral triangles aredrawn, two of them being joined… … rf /V-^^- M. /cS>^ lar faces, the triangles being isosceles, not equilateral.By using plan No. 130, and prolonging the arcs inwhich each set of four triangles is drawn, until the
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