Build It Yourself——-An Educational Robot Mini Solar Kit. The Kit includes complete parts and instructions for building the Happy Hopping Frog. Loads of Educational and Fun Activity. (Recommended for ages 10 and up) Here is the action almost comical, this little green amphibian friend leaps with a joyful sense of freedom. Using its hind legs and rubber feet, Happy Hopping Frog jiggles its eyes as a dog would wag its tail acknowledging its love and appreciation to its owner.