Confusion Icon in Material Style

This Confusion icon is made in Material Design style developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 4,700 icons, all in the same style and quality.
The image is a person's bald head. The person is facing the right and doesn't have a mouth or eyes. The person also doesn't have ears but there is a question mark on the person's head where the ear would be.

Idea of Confusion Icon by Anonymous

We've received the idea on November 01, 2012 and created the icons on April 13, 2013

Math, Science, Social Studies, Language Arts, etc.