Sudoku
From Tardis Wiki, the free Doctor Who reference
A sudoku was a number-based puzzle which was solved with pen and paper. Sudokus of various difficulties were printed in the local newspaper of Winchelham. (PROSE: I Am a Dalek [+]Loading...["I Am a Dalek (novel)"])
Within the sphere chamber, Rajesh Singh reported to Yvonne Hartman that he was on "Sudoku book 509". (TV: Army of Ghosts [+]Loading...["Army of Ghosts (TV story)"])
At the end of a long day, Colin Colchester-Price relaxed by doing Sudoku. (AUDIO: A Kill to a View [+]Loading...["A Kill to a View (audio story)"])
