StdDraw can be found at

http://introcs.cs.princeton.edu/java/stdlib/StdDraw.java

Define two drawTriangles methods, one non-recursive, and one recursive method. The non-recursive version simply calls the recursive version. The recursive version will draw a "level n" Sierpinski triangle. A "level 1" triangle is just an ordinary equilateral triangle. A "level n" triangle is made up of three smaller "level n-1" Sierpinski triangles, as defined below