Schubert, Hermann, 1848-1911 · Chicago : Open Court Pub. Co. ; London : Kegan Paul, Trench, Truebner · leaf 102
ints 3-4, 2-4, 2-3, also must ultimately lie in a straight line, consists in the simple fact that the plane of the three points 2, 3, 4, must cut the plane of the drawing in a straight line. The figure here considered consists of ten points of which sets of three so lie ten times in a straight line… … Fig. 37- ties, may be obtained from the section of a figure of four-dimen- sioned space. Imagine six points, i, 2, 3, 4, 5, 6, situated in this four-dimensioned space, and every three of them connected by a plane, and every four of them by a three-dimensioned space. We shall obtain thus twenty…
