Recursion - Building Java Programs: A Back to Basics Approach - page 750

Figure 12.2

Sierpinski triangle, level 2

We apply this principle in a recursive manner. Just as we replaced the original tri-
angle with three inner triangles, we replace each of these three triangles with three
inner triangles to obtain Figure 12.3 with nine triangles in level 3:

Figure 12.3

Sierpinski triangle, level 3

This process continues indefinitely, making a more intricate pattern at each new
level. Figure 12.4 shows the result at level 7:

Figure 12.4

Sierpinski triangle, level 7

We can solve this problem using the DrawingPanel class from Supplement 3G.
We'll pass the Graphics object for the panel to the method that is to draw the