Tangents

This is one of those things in drawing and design that a lot of people don't know about. Its something called a tangent. Tangents are a bad thing to have in a drawing because they can flatten out and confuse the shape or shapes in the drawing.

It is caused when the edges of two forms touch. This is a diagram that I made a year or so ago for a book I made in design class. I think it illustrates the idea nicely so i may include this in some critiques.