Obtuse Angle

This is an oil rig that represents an obtuse angle. An obtuse angle is any angle greater than 90 degrees/right angle and the underlined piece is greater than 90 degrees.This oil rig is used to extract and collect oil from the sea and is specific to the oil industry.

I found this image online at  http://www.politico.com/blogs/jonathanmartin/0808/McCain_finally_gets_to_oil_rig.html