Loops Are Fun (You Can Say That Again) 57
4, and 5 a total of four times, generating a rosette of four circles
on the top, left, bottom, and right sides of our window. Let’s take
a step-by-step look through the loop as it draws our rosette, one
circle at a time.
- The first time through the loop,
our counter x has a starting value
of 0 , the first value in the range
list [0, 1, 2, 3]. We draw our first
circle at the top of the window with
t.circle(100) and then turn the
turtle to the left by 90 degrees with
t.left(90). - Python goes back to the beginning
of the loop and sets x to 1 , the sec-
ond value in [0, 1, 2, 3]. Then it
draws the second circle on the left
side of the window and turns the
turtle left by 90 degrees. - Python goes back through the loop
again, increasing x to 2. It draws the
third circle at the bottom of the win-
dow and turns the turtle left. - On the fourth and final time through
the loop, Python increases x to 3 , then
runs t.circle(100) and t.left(90) to
draw our fourth circle on the right side
of the window and turn the turtle. The
rosette is now complete.