In geometry, a paraboloid is a quadric surface that has exactly one axis of symmetry and no centre of symmetry. The hyperbolic paraboloid is a doubly ruled surface: it contains two families of mutually skewed lines. The lines in each family are parallel to a common plane, but not to each other. Hence the hyperbolic paraboloid is a conoid. It is also a saddle surface, as its Gauss curvature is negative at every point.
The hyperbolic paraboloid may be generated by a moving line that is parallel to a fixed plane and crosses two fixed skewed lines. This property makes it simple to manufacture it from a variety of materials and for a variety of purposes. The most well-known example is Pringles fried snacks but there are also many examples in architecture, including St. Mary’s Cathedral, Tokyo, Japan (1964), Cathedral of Saint Mary of the Assumption, San Francisco, California, USA (1971), Saddledome in Calgary, Alberta, Canada (1983), L’Oceanogràfic in Valencia, Spain (2003) and London Velopark, London, UK (2011).