Drawing squirals using the python turtle

The Python Turtle can be used to draw a number of interesting shapes. The general method is to:

• Create a turtle
• Set its line colour, width, drawing speed, the length of the first line to be drawn to a value, such as 2 pixels, and the angle the turtle is to turn through after each line segment is drawn (e.g. 90 degrees)
• Set its pen to the pen up position
• Go to the point where the drawing is to start
• Put the pen down
• Draw a line of a set length from the starting point towards the right
• Turn the turtle through the previously set angle
• Add a few pixels to the length of the next line to be drawn
• Repeat the line drawing, turning and line lengthening as many times as is wanted

If the turning angle is 90 degrees then the shape drawn will be a squiral. Here is some code that will do that.

import turtle

wn = turtle.Screen()
wn.bgcolor(0, 0, 0)

t = turtle.Turtle()

t.speed(0)
t.penup()
t.pensize(1)
t.pencolor(255, 0, 0)  

number_of_lines = 100
line_length = 2
line_length_increase = 2
turn_angle = 90
 
t.pendown()  
for _ in range(number_of_lines):    
    t.forward(line_length)  
    t.left(turn_angle)   
    line_length += line_length_increase
t.penup()

To draw more interesting shapes use an angle other than 90 degrees. The program used in this repl does that by choosing a random angle. The line colour and number of lines drawn are also randomised.