TARDIS were not, its weight would shatter the Earth's surface. In the tie-in novels, the interior of the TARDIS has been known to contain an entire city, encompass an entire parallel Earth, and even dwarf Gallifrey itself when turned inside out. A distinctive architectural feature of the TARDIS interior is the roundel. In the context of the TARDIS, a roundel is a circular decoration that adorns the walls of the rooms and corridors of the TARDIS, including the console room. Some roundels conceal TARDIS circuitry and devices, as seen in the serials "The Wheel in Space" (1968), "Logopolis", "Castrovalva" (1981), "Arc
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