Animation Transitions, Mechanim, Animator Overview Gizmos.

I am working alot with Unity's Mechanim system lately.

I Want to know if somebody knows what the following things are, I can't find explanations for them in the documentation.

1 - why is that gizmo sometimes taking that shape?

2 - why is the right gizmo does not take that shape?

3 - why is there sometimes a line here? what does it mean?

4 - does this gizmo have any effect at all on animations, what purpose does this gizmo serve?

And a more specific question. when a transition condition is specified by a bool or trigger. then does the positioning of the "transition into" animation have any effect on the transition? cause it feels like I can transition at any point from the "transition from".

Is there a way control where into the "transition into" animation, i transition, when transitioning?