Bent tree polyomino
A bent tree is a polyomino that is orthogonally directed from two adjacent directions. It's like a tree except "bent" diagonally as if it were growing on a slope. It is similar to an antler, except instead of a single anchor cell in the corner, there can be multiple anchor cells along the border.
Symbol
Regex
ru(ru|lu|ld(ld)*lu)ld(ld)*(rd)*