Clones

They've assured us that they are clones.  The younger, on the left, explains that they were so identical, that she spent her entire life savings...all that she had, plus all she will ever get...to make herself look slightly different, so they wouldn't look exactly alike.
Best friends working hard to retain their own identity, while enjoying the ways in which they are just alike.  Few things in life will ever compare to all they've shared, or the fun they've had.