It seems very subjective. There are letters where you start with the curve and end with the straight line, like lower case d. So for the mirrored B there's noth

It seems very subjective. There are letters where you start with the curve and end with the straight line, like lower case d. So for the mirrored B there's nothing wrong with starting with Ɛ and adding the straight line afterwards. So still, the final choice seems pretty arbitrary to me.