World 5 - Level 3
Collect all Rainbow Coins ("C") and Bonus Coins ("B"). Move the hidden wooden box along the green path into the water, and roll the hidden boulder from the yellow position into the water. Now move the steel box along the purple path to the purple "X", and roll the hidden blue boulder up toward it. It is now also in position to be rolled into the water, but don't do it yet! Use the steel box instead to complete the bridge, and roll the boulder of the completed bridge into the row of Coilys. The path to the exit is now free.