Got nothing to do for a few hours? Are you sure? Because this can be a massive timesink.

2048 is a game played on a 4x4 grid. Two squares have numbers in them. You use the arrow keys to move all numbers that can be moved in that direction as far as they can go. (Numbers that can't are numbers that are against an edge in that direction anyway, and unequal numbers that have that number next to them in that direction.) Each time you move the numbers, a random empty square is filled with another number. When a number runs into a number that is equal to it, the blocks combine into one with the combined value of both.

The objective is to make a 2048 block. The lose condition is if all squares are filled and you can't combine any.

Have fun!