Learn, enjoy the operation, collect the series
The latest release in Academy's Edutainment Series is the (18156) Kayak Robot. It is powered by a motor that creates a reciprocating rowing motion. This movement in turn drives the paddles to propel the boat. It can run in bath tub, fish tank or other container. Easy to assemble, it needs no glue. The Robot Kayak demonstrates the principles of mechanical link and joint mechanisms. And it's fun.