of the earliest uses of computers in structural analysis, to understand the complex forces to which the shells would be subjected. The computer system was also used in the assembly of the arches. The pins in the arches were surveyed at the end of each day, and the information was entered into the computer so the next arch could be properly placed the following day. In mid-1961, the design team found a solution to the problem: the shells all being created as sections from a sphere. This solution allows arches of varying length to be cast in a common mould, and a number of arch segments of common length to be placed adjacent to one another, to form a spherical section. With whom exactly this solution originated has been the subject of some controversy. It was originally credited to Utzon. Ove Arup's letter to Ashworth, a member of the Sydney Opera House Executive Committee, states: "Utzon came up with an idea of making all the shells of uniform curvature throughout in both directions." Peter Jones, the author of Ove Arup's biography, states that "the architect and his supporters alike claimed to recall the precise eureka moment ...; the engineers and some of their associates, with equal conviction, recall discussion in both central London and at Ove's house." He goes on to claim that "the existing evidence shows that Arup's canvassed several possibilities for the geometry of the shells, from parabolas to ellipsoids and spheres." Yuzo Mikami, a member of the design team, presents an opposite view in his book on the project, Utzon's Sphere. It is unlikely that the truth will ever be categorically known, but there is a clear consensus that the design team worked very well indeed for the first part of the project and that Utzon, Arup, and Ronald Jenkins (partner of Ove Arup and Partners responsible for the Opera House project) all played a very significant part in the design development. As Peter Murray states in The Saga of the Sydney Opera House: The design of the roof was tested on scale models in wind tunnels at University of Southampton and later NPL in order to establish the wind-pressure distribution around the roof shape in very high winds, which helped in the design of the roof tiles and their fixtures. The immensely complex design and construction of the shells was completed by Hornibrook Group Pty Ltd,