Licks, H. E · New York, D. Van Nostrand company · leaf 70
61 GEOMETRY ciently indicated by the arrowheads on their perimeters. We append an example (Fig. 23). … Fig. 23 In this case the tangle reduces to a negative loop a and to a large positive loop b, within which are two other positive loops c and d, the former of which contains a fifth small positive loop e. The area of the entire tangle then equals b+c+d+e— a. The space marked s in the first figure…
Mathematical recreations
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