One of three single surface models in yellow wire showing a Cross Cap, 1967. One of three single surface models in yellow wire 1967
One of three single surface models in yellow wire showing Hilbert's model, 1967. One of three single surface models in yellow wire 1967
Selection of three single surface models in yellow wire showing; (a) Cross Cap, (b) Boy's surface, (c) Hilbert's model, 1967. Selection of three single surface models in yellow wire showing 1967