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."[38] Yuzo Mikami, a member of the design team, presents an opposite view in his book on the project, Utzon's Sphere.[41][42] 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.[43]