POLL RELATED POST
So someone recently asked me "Why do Space Marines have square butts?" I of course had no answer. There is nothing in the fluff to indicate why. It is just the way they are.
I came up with some ideas though
Helps them stay in their seats on T-hawks and in Rhinos due to increased surface area.
When sitting next to each other, they fit together like stacking chairs.
Measure right angles/level surfaces (indicator on their hud, data fed from some interal sensor).
"Butt"butt things.
Sit on uncomfortable stone thrones (Marneus Calgar)
Drop Pods clamp on there.
So vote one what you think. If you have a better idea, tell me please.
POLL RESULTS
Helps them stay in their seats on T-hawks and in Rhinos due to increased surface area. 6 (33%)
When sitting next to each other, they fit together like stacking chairs. 1 (5%)
Measure right angles/level surfaces. 3 (16%)
"Butt"butt things. 2 (11%)
Sit on uncomfortable stone thrones. 0 (0%)
Drop Pods clamp on there. 2 (11%)
Other (please put in comments). 4 (22%)