On the Subject of Directing Buttons

Hey, isn't that Colored Squ--

This module presents a 4x4 grid of buttons, each coloured red, yellow, green or blue. These buttons represent a path taken through the grid, so that every square within it has been visited exactly once after 15 moves (where red means a movement up, yellow means a movement to the right, green means a movement down and blue means a movement left). To solve the module, press the button that is the starting point of the path. Pressing the wrong button will cause a strike.