Goal and options: How can you limit soap usage?
output answer: To limit the quantity of soap used, place several rubber bands below the top of the pump on soap dispenser, this will reduce the amount in each pump.

Goal and options: To make an iron man helmet with the face plate that opens up.
output answer: Attach the face plate to the rest of the helmet at the top using a servo motor. Attach a switch to move the face plate up using the motor.

Goal and options: How to attach the track pieces of a toy train set?
output answer:
Take individual pieces and attach them together by latching them on their groove.