# Optical Illusions Which of the above two purple circles is bigger?

#### Learning Objectives

In this challenge you will use Python Turtle to draw geometric shapes and optical illusions.

• drawLine() to draw a straight lines between two points,
• drawSquare() to draw a square of a given size and colour,
• drawCircle() to draw a circle of a given size and colour.

To position these shapes on the screen you will need to use x,y coordinates and pass these coordinates when using the three functions given above.

#### (X,Y) Coordinates

The canvas we are drawing on (using Python Turtle) is 400 pixels wide by 400 pixels high.
Look at the canvas below to understand how (x,y) coordinates work: #### Check the code

Complete the code given to draw the following optical illusions: Which of the above two purple circles is bigger? Which of the above two lines is longer? Which of the above two lines is longer? Are both purple lines perfectly straight? Are all the white dots really white? Tagged with: ,