Answer: Turtle Challenge #213

Here’s what the code from Turtle Challenge #213 draws. This picture was made by running the code for real.

The drawing made by turtle challenge 213.
What the turtle drew.

The answers

How many circles will the turtle draw? 36 circles, one each time round the loop.

Why does the turtle turn 10 degrees after each circle? Because 36 × 10 = 360, so the circles spread evenly all the way round, like petals on a flower.

What colour is the flower? All limegreen.

How the code works

t.circle(40) draws a whole circle and brings the turtle back to the same spot. Turning a little between circles makes a flower pattern.

import turtle

t = turtle.Turtle()
t.speed(0)
t.pensize(2)
t.pencolor("limegreen")

for petal in range(36):
    t.circle(40)
    t.left(10)

t.hideturtle()
turtle.done()

Try it: What happens if you use t.circle(40, 180) instead? (That draws half a circle.)