Take turns with a friend trying to design the most effective urban camouflage. Using the most hallowed of ninja skills, the "hold up a sheet with a picture of a wall on it" technique is your only defense. Can you design a clever enough sheet to fool your friends? Can you see through their own illusions in time to find the skunk?

When the game starts, one of the two players should sit down, while the other should look away. (the game will tell you when it's ok to have them look again.) You have around 40 seconds now to click and drag icons onto the square below, to make it look like the highlighted area above.

Once time is up, player 2 comes back over, and gets to try to spot it, scrolling through the city, looking for things that look ... off. They get one try to find you, and are scored on how long it takes.

Then you switch!

At the end, the game ranks both of your performances, and awards the coveted title of victor to someone. Fun for the whole family!

Warning: Artists tend to be terrifyingly good at this game.