forked from: forked from: adobe challenge 1 (Elastic Rectangle)

"Use Flash Player 10 drawing API,
*  specifically drawTriangles.
*  My favorite part of the new capabilities
*  is the ability to specify
*  UVT texture mapping data."
*                     by Justin Everett-Church
*  
* This code is a example of drawTriangle.

ぐにゃぐにゃ矩形 
* "a" キーでアンカーの、"j"キーでジョイントの表示・非表示が切り替わります
* 解説
* http://aquioux.blog48.fc2.com/blog-entry-623.html
