| 摘要 |
n being a number of the arithmetic progression 6 - 10 - 14 - 18 ... with common difference 4, solid volumes obtained by juxtaposition, base against base, after rotation through 360 DEG /n of one of them, of two equivalent pyramids 1 and 2 with regular polygonal bases of n/2 sides, these bases forming, with the lateral faces, an angle of 45 DEG and preserving only the part included in a cylinder of identical axis and whose cross section is the circle 4 inscribed within the two bases (elimination of the parts 6). Each of the faces may receive a different or repeated sign. Examples: two decahedra - top view in Fig. - one for the units, the other for the tens, permit selection of the numbers for the National Lottery. A 30-face polyhedron may be used, for the same purpose, for three-horse forecast betting. <IMAGE>
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