I like just amoms idea, it is mine too, I say keep the a squared and put the arrow inside and make it curvy to give some softness to it to create the negative space :) Kind of a triangle for arrow tip but connected to stem with thin at the bottom of triangle then flair out to look like the base of a treethen strait down near bottom...ha ha dont know if I explained well, I am an artist but not very computer savvy.