Enjoy and leave a comment!
Step 2: Building
Than add an additional leg on each side. You don't have to change the gearing mechanism at all. The entire leg mechanism is even simpler because you don't have to worry about tripod gaits. (The new leg is the white leg).
(Sorry about slightly blurry photos - exposure time was 13)
Step 3: Everything else
I used NXT-G programming software, but you have many other choices as well...
Please leave a comment!