Here's another example of the power of recursion. Study it carefully and try to figure out what's happening. Check.

So, we draw a V and, at the end of each arm, we draw a smaller V.

Exercise 19 Teach the turtle to draw a single V. Check.

Exercise 20 Have a go at finishing the tree - incredible adulation if you can do it without peeking! Check.

Exercise 21 Adjust the numbers for a more pleasing result.