Mechanism of "Earth Park !"

This is a mechanism to make the Whale's blowing water up and down. The blowing becomes high and low.

This is a mechanism to make the Alligator's tail swing. The tail moves at the constant swing.

Each mechanism uses a "MINDSTORMS RCX", respectively.

And then, cover the trains with the walls of Earth.

The wall of Earth can be also divided into four parts. Fix it with peg-parts.

And then, fix the top of the walls with plate-bricks.