In humans, chimerism is a rare genetic disorder where the blood contains two genetically distinct blood types, featuring more than one set of DNA. You lived alone, first by choice, then out of habit, perched in the drafty window sill with the pothos and the schefflera, studying the starlings, so separate from the shatter and gasp. And then you were twinned, born one May, quietly mewling, wet fingers reaching. The routine operation, after which the doctors introduced you to yourself. Chimerism, they said, shadow wombed. You are: a sister self. You are: born wet and two. You are unmade. All you heard was the gentle rush of the word twin. A breath slipped through your lips you didn’t know you were holding. You met yourself the pushy nose of a twinflower edging above the surface of the dirt. The linneae borealis nodded in the woods, two pink heads blushing and conspiring.