What is right IK rigging for this mechanism?

i have no idea what could be possible the right rigging for this thing?
reff : https://www.youtube.com/watch?v=NM4q-f68TlY

In the description there is a link to the blend file.
Edit
I have seen there is a dependency cycle but it sort of works I will have a go to get rid of the dependency.

Changing the Ik chain length of bone.006 to 2 seems to have solved the dependency.

walker2.blend (83.0 KB)

Credit should go to the author of the video post Executive Quest
I simply changed the chain length of one bone!

wow! you even find the youtube tutorial for this.
this is incredible!
many thanks to you man! i really love it.