GCSE CS Turtle Revision

1 Theory & Coordinates 📐

1. The Grid System

Recall the Cartesian coordinate system used by Turtle.

a) Coordinates (x,y) of "Home":

b) Command to go to center:

c) If left edge is x = -200, right edge x is?

2. Headings & Orientation

Match degrees to compass directions.

0° East (Right)

90°

180°

270°

3. Drawing Mechanics

a) Name the two formats for defining color:

1.

2.

b) Why do "layers" matter when drawing a target?

2 Code Comprehension & Debugging 🐞

The code below is supposed to draw a blue pentagon. There are 4 errors. Find and fix them.

Buggy Code:

import turtle t = turtle.Turtle() t.colour("blue") # Error 1? # Draw a pentagon for i in range(5) # Error 2? t.forward(100) t.right(60) # Error 3? t.hideturtle() turtle.done()

Hint: A pentagon has 5 sides. The external angle is 360 / 5.

Your Corrected Code:

3 Coding Challenges ⌨️

Task A: The Starburst Pattern

Instructions:

The turtle must start at the center (0,0) for every line.
It must draw a line 100 pixels long, then return to the center.
It must change angle by 90 degrees after every line.
Crucial: You must use a for loop to iterate through the colour_list.
Use setheading or simple right/left turns.

Task B: Concentric Squares (Subprograms)

Write a program from scratch to draw Concentric Squares centered at (0,0).
Requirement 1 Define draw_centered_square(size, fill_color).
Requirement 2 Use penup() and goto() to center the shape (offset by size/2).
Requirement 3 Call function 3 times: Black (200), Red (150), Yellow (100).

Python Turtle Revision 🐢