Norwegian engineer Kåre Halvorsen (Zenta), inspired by nature insects, has built hexapod robots since 2006. The latest robot that he made is called MorpHex MKII. This six-legged robot can not only walk but roll in the straight line.
The previous generation, MorpHex MKI, could only roll in a curved direction. Zenta decided to use two servo motors on each leg, and made legs have 2 DOF. That is, MKII can be controlled easier.