Hilbert curves. A space-filling curve is a continuous curve in the unit square that passes through every point. Write a recursive Turtle client that produces these recursive patterns, which approach a...

Hilbert curves. A space-filling curve is a continuous curve in the unit square that passes through every point. Write a recursive Turtle client that produces these recursive patterns, which approach a space-filling curve that was defined by the mathematician David Hilbert at the end of the 19th century.

Partial answer: Design a pair of mutually recursive methods: hilbert(), which traverses a Hilbert curve, and treblih(), which traverses a Hilbert curve in reverse order. See the booksite for details.