A cool visualisation of the recaman sequence. It draws arcs alternatingly above and below the number line from the previous number in the sequence to the next. Inspired by Numberphile - see below.
The sequence starts at 0. To get the second number, I try to subract 1. To get the third, I try to subtract 2, and for the fourth, I try to subtract 3, etc. The catch is that if by doing that, I land on a number which I've already seen, or one which is negative, I increment by that number instead.