insert case 1
insert case 2
insert case 3 flip colors parent uncle
insert case 4 rotations
insert case 5 adjust colors and rotate
insert case 5 adjust colors and rotate
simple remove
delete case 3 brother children are black make him red
delete case 4 brother has black children but parent is red make brother red
delete case 5 brother has red child, make child black
delete case 6 make parent black
min key
simpler types