Collision shapes. Do´s and dont´s

Just to be sure

1. What kind of shapes are forbidden or denied? Overlapping lines in collision points?

2. Concaving shape? (I can´t remember correctly but I think that somewhere was mentioned that these kind of "U-shapes" should be avoided)

Tried to check for manual but could not find any mention about "forbidden" shapes

Overlaping lines I think ends up in an error at runtime.

U shapes were related to both shadow caster and physics If I Recall Corectly.

Concave shapes are fine with the physics behavior.