Walker up tube

[the stig]

hey,
has anyone been able to make a walker that can make it up tube? me and a friend have been working on getting one going and we managed to get it going, but it still requires a push from the roller underneath. anyone able to get one that can work just on legs?

here is my design
http://FantasticContraption.com/?designId=844514

i really wanna see what you guys can come up with.

[WhyT]

Tough challenge. I modified yours can go get it to take one step but that was all.