"In keeping with the great secrecy involved in India's efforts to develop and test its first nuclear explosive device, the project employed no more than 75 scientists and engineers working on it in the period from 1967 to 1974. Of course this does not count the thousands of individuals required to build and operate the infrastructure supporting BARC and to produce the plutonium for the device. Outside of those actually working on the project, only about three other people in India knew of it - Prime Minister Indira Gandhi, her trusted adviser and former principal secretary P.N. Haksar, and her current principal secretary D.P. Dhar. No government ministers, including the Defense Minister, were informed. The implosion system was designed to compress the core to twice its normal density. The lenses that were developed used the fast-slow explosive design pioneered by the U.S. in World War II. Like the Gadget exploded at Trinity in 1945, they used an RDX-TNT mixture as the fast explosive, with baratol (barium nitrate and TNT) used as the slow explosive. Chengappa describes the inner slow explosive component as being in the shape of "Shiva ling am" -- a phallus in Hindu religious art which is squat and blunt in form. The device used 12 lens, which is described by Chengappa [pg. 182]: "the way the explosives were placed around the plutonium sphere resembled the petals of the lotus". This presumably indicates that each hemisphere of the implosion system consisted of 6 longitudinal lens segments (asymmetric diamond shaped lenses) joined together at the pole so that they formed triangular teeth at the equator which interlocked with the opposite hemisphere. This design is simpler and less sophisticated than the 32-lens "soccer ball" system developed by the U.S. during World War II."