T. Sundara Row's Geometric exercises in paper folding; (1901)
Sundara Rao, Tandalam, 1853-, Beman, Wooster Woodruff, 1850-1922. ed, Smith, David Eugene, 1860-1944. ed · Chicago, The Open Court Pub. Company; [etc., etc.] · leaf 106
IN PAPER FOLDING. 87 161. If a figure has two axes of symmetry at right angles to each other, the point of intersection of the axes is a center of symmetry. This obtains in reg- ular polygons of an even number of sides and certain curves, such as the circle, ellipse, hyperbola, and the lemniscate;… … Fig 54- sides may have more axes than one, but no two of them will be at right angles to each other. If a sheet of paper is folded double and cut, we obtain a piece which has axial symmetry, and if it is cut fourfold, we obtain a piece which has central symmetry as well, as in Fig. 54.
Geometry · Paper work
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