Fludd Ladder

Here is the picture of Robert Fludd's ladder used by Tiller as the basis for his sculpture. There's some sort of geometry made out there which I can't quite make out. I found it here at the JR Ritman Library (which I am going to spend a lot of time at over the next few weeks). It was in the book with rather grandiose title Utriusque cosmi maioris scilicet et minores metaphysica, physica atque technica historia.