The premise is magical. The screen is a yellowed, unfolded piece of paper, and your mouse cursor is a crayon. What you draw on the paper comes to life. Draw a circle and it will roll down a slope. Draw a line between two points and it becomes string. Attach a hurriedly drawn square to one end, and something you want to lift to the other, and you've made a primitive rope and pulley system. Draw a box with two wheels and there's a little vehicle. The miracle of Crayon Physics Deluxe is that all this works. Like some kind of amazing wizard, you get to draw objects and then immediately see them animated in front of you. What a treat.