Idea of Copy Icon
It's two folders, one slightly indented and they're standing perpendicular to each other. They are both rectangles, with slight triangular curves in the top right as if you're folding a piece of paper. The purpose of it is to copy anything and make a second copy of it. They both are the same size, height, and would stand up next to each other identically.
This is a Copy icon. It is available in PNG and vector. Downloading is free for PNGs up to 100x100px.