**Python Turtle Cheat Sheet**

- turtle.pen(pencolor=”red”, pensize=10, fillcolor=”black”): Pens have attributes such as color, size, and fillcolor.
- turtle.up(): Sets the pen state to be up (not drawing). turtle.down(): Sets the pen state to be down (drawing).
- turtle.right(degrees): Turns the direction that the turtle is facing right (clockwise) by the amount
- indicated (in degrees). turtle.left(degrees): Turns the direction that the turtle is facing left (counter clockwise) by the amount indicated (in degrees).
- turtle.forward(distance): Moves the turtle forward (in the direction the turtle is facing) the

distance indicated (in pixels). Draws a line if the pen is down, not if the pen is up. turtle.backward(distance): Moves the turtle backward (in the direction opposite to how the turtle is facing) the distance indicated (in pixels). - turtle.setheading(angle): Sets the orientation of the turtle to angle. Here are some common

directions in degrees: 0 (east), 90 (north), 180 (west), 270 (south). - turtle.goto(x,y): Moves the turtle to the specified coordinates, drawing a straight line to the

destination (x,y) if the pen is down, and not drawing if the pen is up. - turtle.circle(radius): Draws a circle of the indicated radius. The turtle draws the circle tangent to the direction the turtle is facing.
- turtle.fill(True): To fill a figure, use turtle.fill(True) before you start drawing the figure. The figure drawn will be filled with the present color setting.
- turtle.hideturtle(), turtle.showturtle(): Sets the state to hide / show the turtle. When shown, you see it as a small arrowhead pointed in the direction of the heading.
- turtle.xcor(), turtle.ycor(): Returns the x-coordinate / y-coordinate of the current pen position.
- turtle.bye(): Close the turtle drawing window.

# "A black and red triangle" import turtle turtle.pen(fillcolor="black", pencolor="red", pensize=10) turtle.fill(True) for _ in range(3): turtle.forward(100) turtle.left(120) turtle.fill(False) # "A spiral out of squares" import turtle size=1 while (True): turtle.forward(size) turtle.right(91) size = size + 1 #"A nautilus shape" import turtle size=1 while (True): for _ in range(4): turtle.forward(size) turtle.right(90) size=size + 1 turtle.right(10) #"A yellow star pattern" import turtle turtle.pen(pencolor='red', fillcolor='yellow') turtle.fill(True) while True: turtle.forward(200) turtle.left(170) if abs(turtle.pos()) < 1: break turtle.fill(False) turtle.done() #"Recursive Star" import turtle def star(turtle, n,r): """ draw a star of n rays of length d""" for k in range(0,n): turtle.pendown() turtle.forward(r) turtle.penup() turtle.backward(r) turtle.left(360/n) def recursive_star(turtle, n, r, depth, f): """At each point of the star, draw another smaller star, and so on, up to given depth. Rescale the stars by a factor f at each generation.""" if depth == 0: star(turtle, n, f*4) else: for k in range(0,n): turtle.pendown() turtle.forward(r) recursive_star(turtle, n, f*r, depth - 1,f) turtle.penup() turtle.backward(r) turtle.left(360/n) fred = turtle.Turtle() fred.speed("fastest") recursive_star(fred, 5 , 150, 4, 0.4)

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