having already tested the hot wheels circuit on the theme of piranha, I bought for my 5 year old son shark circuit. He loved it, but ... the principle of the game is to immerse the car in the basins of warm water and cold water so that the car changes its color under the effect of the temperature difference .. she changed the color of her once out of the box and then .. nothing .. she is white. Too bad. Fortunately, the circuit is completed and fun ways we just purchased separately create something nice ... For info: the car comes with the piranha circuit has had the same problem, but after a longer period of play and joy ...