The steps in the image show the evolution of the design: we started with an image where the two halves of a woman (representing the two sisters) share the same heart, one same soul, with their initials added.

Stylizing it we used the letters themselves to form the arms and we split the design into two halves completing them with wings shaping two butterflies, to symbolize the beauty and preciousness of their bond, so that each of them can ink the butterfly with the headletter of the other.