Smooth Moves

You scatter your Micro Machine cars and marbles strategically around the front entrance. The physics is beautiful – tiny metal cars plus marble ball bearings equals a surface slipperier than an ice rink.

To complete the effect, you add a light coating of cooking oil near the door. Anyone trying to make a stealthy entrance is going to have a very unstealthy landing.

As you put the finishing touches on your slip-trap masterpiece, you hear footsteps approaching the front door. Time to see if your calculations were correct!