TARDIS to those first seen in 1963, with multiple roundels illuminated from behind. The fourth major redesign of the TARDIS in the revived series appeared in the eleventh series. New production designer Arwel Wyn Jones said that the inspiration for the Thirteenth Doctor's TARDIS was based on the 2005-10 model, which he had worked on. The console room is the "safest place on the ship," and so when its occupants are in danger the TARDIS will reinvent its architecture so as to allow them to enter the console room. This can also result in the TARDIS materialising itself within its own
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