I'm confused...

That is a figure four with a "cage" replacing the "deadfall".

You can always lash sticks parallel to one another like a raft, and place other objects on top to give you the weight you need to crush the critter in question. It will give you more options on how to balance the whole shebang than an individual log will.

Or were you just siting that particular trap as a way to practice without killing?

I'm sorry, I'm completely lost.