41. In the early years of relativity the hyperboloid model was used by Vladimir Variak to explain the physics of velocity. 42. In the 1970s, Genzken began working with wood that she carved into unusual geometric shapes such as hyperboloids and ellipsoids. 43. The curves of constant \ zeta are oblate spheroids and the curves of constant \ xi are the hyperboloids of revolution. 44. This concrete-framed hyperboloid structure, appears with its glass roof to be reaching up, open, to heaven. 45. In the crypt the large hyperboloid stained glass windows stand out, with the shapes of flower petals and butterfly wings. 46. Whereas the Gaussian curvature of a hyperboloid of one sheet is negative, that of a two-sheet hyperboloid is positive. 47. Whereas the Gaussian curvature of a hyperboloid of one sheet is negative, that of a two-sheet hyperboloid is positive. 48. Hyperboloid structures were used starting towards the end of the nineteenth century by Vladimir Shukhov for masts, lighthouses and cooling towers.49. Jeatd Tower is a reinforced concrete construction with a shape called " hyperboloid ", built between 1963 and 1968. 50. Isaak Yaglom illustrated a two-step compactification as above, but with the split-complex plane tangent to the hyperboloid .
