Kangar Gravity Simulation on Diamond Structure

Hello,

Im trying to create a Kangaroo gravity simulation on a diamond shape to investigate its structural integrity. I'm not quite sure where I'm going wrong but it seems when I run the simulation the gravity force does not have any effect on the shape? Any idea where I might be going wrong?

My file is attached below. Thank you in advance.

Week%209.1%20HW%20-%20Zahra%20Said%20-%20diamond%20kangaroo%20gravi...