The bisector of the outer corner of one acute angle OBA is set to L 1 and L2 clockwise, and the bisector of the other acute angle A is set to L3 and L4 clockwise.

Then l 1∨l4, L2⊥L3

L 1 intersects L3.

L2 intersects L4.

The degree of intersection is uncertain, which is related to the size of ∠OAB.

For reference! JSWYC