New to Lego? Curious about gears, pulleys and stuff? The Lego Constructopedia has cool graphics that illustrate how you can use gears and pulleys to do various things.
Take this quiz and try to solve the problems before you click on the answers.
1. How do you make two pulleys connected by a belt to turn in opposite directions? Or, how would you reverse the direction of rotation when using two pulleys? (Answer)
2. How would you use pulleys to change the direction of rotation by 90 degrees? (Answer)
3. How would you make two axles connected by gears to turn in the same direction? (Answer)
See other cool demos at the Constructopedia.