Pathfinder is a small JavaScript game based on a video game mini-game is used to play.
You can play it at : https://mark.poussard.io/pathfinder/
The aim of the game is to - starting from the green square - pass through every square once and only once and end on the final blue square.
To do so you should drag the light green square through the map, squares you have already gone through will turn dark green.
If you are stuck you can reset the level and start again.
There are 8 levels of varying difficulty, you can skip through to any one of them by clicking on the left hand menu.