Quoting from Wolfram Mathworld: " It is the shape used in the construction of soccer balls, and it was also the configuration of the lenses used for focusing the explosive shock waves of the detonators in the Fat Man atomic bomb (Rhodes 1996, p. 195)." but further insights are not provided. (http://mathworld.wolfram.com/TruncatedIcosahedron.html)
Why would the Manhattan project scientists choose this geometry for designing the implosive lenses of the Fat Man atomic bomb? Assuming the explosive charges were placed on the faces of the icosahedron, is this the optimal geometry for focusing the shock waves on a single point (presumably a spherical plutonium core), or was this mainly due to practical/engineering considerations?