TARDIS tight schedule, which led to Brachacki leaving the show due to disagreements with the production team and possibly a feeling that he had been given an impossible task. Despite his leaving the show and mixed reactions as to how the set looked (producer Verity Lambert liked it but director Waris Hussein did not), the basic design of the hexagonal console and wall roundels has persisted to the present day. In the Third Doctor serial "The Time Monster" (1972), the console room of the TARDIS was dramatically altered, including the wall roundels. This new set, designed by Tim Gleeson, was disliked
Hexagonal tortoise problem His book, "Gusuryak", contains many interesting mathematical discoveries. Below is his original magic hexagonal tortoise pattern. All the sums of six numbers of each hexagon are the same number, 93. The magic sum varies if the numbers 1 through 30 are rearranged. For example, the magic sum could be 77 through 109. Hexagonal tortoise problem The hexagonal tortoise problem () was invented by Korean aristocrat and mathematician Choi Seok-jeong, who lived from 1646 to 1715. It is a mathematical problem that involves a hexagonal lattice, like the hexagonal pattern on some tortoises' shells, to the ("N") vertices of which must