-They have basically the same voice

-They have basically the same body

-They have basically the same face

-They must share clothes unless they strip naked every time they go to bed

-Caliborn is Vehemently against girly things and obsessed with being masculine

-Calliope must CONSTANTLY go to sleep in dresses and bows just so that he has to wake up and take it all off again

-But if he does the same Callie just wakes up dapper in suits and suspenders