Iconset for Photoshop guidelines

I've been working on a Photoshop guidelines document for third parties and so far this document has 8 categories: images, colors, guides & dimensions, typography, files, layers, effects and vectors.

I thought it would be handy (and a great exercise) if each category had it's own icon. Since it's my first attempt, I'm quite happy, except for the layers icon. Any feedback would greatly help.

Make sure you check the @2x for all the pixels.