For those slightly concerned with "61. Ends," no, that will not be the last of Erin. It is her last role in Addison's life, but then again, these drabbles aren't in order.
Shapes
If she thinks about it carefully, head tilted to the side, eyes almost closed, a pair of forceps is really just a pointy triangle. A scalpel is a trapezoid. A retractor is a curvy rectangle.
She's careful not to think too much, or else she'll be trapped in a land of magical phantasmagorical shapes, gone like Bastian in Fantasia, thinking that they can do anything.
The shapes only look like they perform miracles.
Reference: Bastian in Fantasia is The Neverending Story, by Michael Ende. Towards the end, Bastian becomes in danger of being trapped in Neverending Land without his memories. Pretty good fantasy, though the films haven't been amazing.