How can I build a tidepool like the one at Monterey bay aquarium?

Question:I want to know how I can I build a tidepool in a back yard. I want a machine that causes water to move gently back and forth like small waves. If you ever been to Monterey bay aquarium, they have a small wave machine in one area with a lttle bit of sand. It's like a small beach and you can see a side view of it as your standing behind the glass. Any help on how to get started on this or any ideas you have would be very helpful? Or if you know cmpanies that make these that would be helpful too.

Answers:
You'll need a good strong motor, a frame, an eccentric(Cam) , a reduction gearbox and a long arm,(Long enough to kep the motor out of the water.) and a paddle.( It could be anything that's long and wide like a plank.)
The paddle needs to be fixed to the fame at one end, but with a flexible joint, rather like a flap, the arm connects to the other end, which in turn is bolted on to the cam which is fitted on to the lower end of the gearbox. The motor connects to the take in end of the gearbox, and when run, the cam moves the arm back and forth, causing the paddle to move too, which when placed in the water creates ripples, and slowly almost wave like tides! the bigger the eccentricity of the cam, the more the movement of the paddle, and consequently, the bigger the waves!