Toby (Fear Itself)
From Tardis Wiki, the free Doctor Who reference
Toby (short for Tobias) was a three-year-old boy the Eighth Doctor met after he had been brainwashed in the 22nd century. At that time, his father was trapped behind an energy barrier and his mother had become one of the Wounded. While playing a join-the-dots game on a computer pad, he created a unicorn-shaped pattern. This inadvertently caused the Doctor to remember who he was when he saw the pad. (PROSE: Fear Itself)