Pneumatic Middle class Switch relay Walker

Lego Technic Pneumatic Switch relay Sample
http://www.youtube.com/watch?v=OFwA4qBQq5A&feature=mfu_in_order&list=UL

Lego Technic Pneumatic Walker Sample
http://www.youtube.com/watch?v=NIxtUx9PFrE&feature=bf_next&list=ULOFwA4qBQq5A&lf=mfu_in_order

Lego Technic Pneumatic Walker2 DRAGON
http://www.youtube.com/watch?v=-L6b1PWUCxg&feature=bf_next&list=ULNIxtUx9PFrE&lf=mfu_in_order