Remember the Bittle: it is a palm sized Arduino Robot Dog for STEM education. It is tiny enough to fit in the palm of your hand. It can be programmed in C and Python. This video shows how this quadruped robot can climb up to the ceiling.
Bittle is driven by nine P1S servos. It has a NyBoard V1 inside. With its Bluetooth dongle, you can interact with the robot through your smartphone.