Lecture 4 — Turtle Positioning & Direction⌗

Instructor: Laksh Budhrani

Review / Recap⌗

Basic Commands from Previous Lectures⌗

Canvas Coordinates & Directions⌗

Canvas Reference Image⌗

The turtle screen works like a graphing plane:

• Center → (0, 0)
• Right → positive X
• Left → negative X
• Up → positive Y
• Down → negative Y

This helps us understand where the turtle will “teleport” when using goto(x, y).
It also shows how setheading(angle) works:

• 0° → face right
• 90° → face up
• 180° → face left
• 270° → face down

These angles help us point the turtle in exact directions before drawing.

Objectives⌗

1. Learn how to teleport the turtle using goto(x, y)
2. Learn how to point the turtle using setheading(angle)

Objective 1 — goto(x, y)⌗

Simple Definition⌗

• goto(x, y) — Move the turtle instantly to a specific coordinate.

Example: Move to Top‑Left Corner⌗

p.goto(-200, 150)

Objective 2 — setheading(angle)⌗

Simple Definition⌗

• setheading(angle) — Point the turtle in a specific direction using degrees.

Example: Face West and Draw⌗

p.setheading(180)
p.forward(100)

Clock Drawing Activity (Guided)⌗

Create a new Python file in VS Code named:
turtle_class4.py

Clock Image⌗

Explain in Plain English⌗

Write a short explanation (3–5 sentences) describing how you think we can draw this clock using:

• goto(x, y)
• setheading(angle)
• penup()
• pendown()
• right()
• forward()

Explain the steps in simple English, as if you are telling a friend how to draw it.

Boilerplate Code⌗

import turtle as trtl

p = trtl.Turtle()
p.speed(0)

# --- ENTER YOUR CODE HERE ---
# (Use goto() and setheading() to place each clock line)



# --------------------------------------------------------------
# (Stop writing code above this line)

wn = trtl.Screen()
wn.mainloop()

Notes⌗

• Use goto() to place each hour mark.
• Use setheading() to point the turtle outward before drawing each line.
• Use penup() to move without drawing.
• Use pendown() to draw the hour marks.
• Use hideturtle() at the end for a clean final look.

Independent Activity — Pine Tree Drawing⌗

Pine Tree Image⌗

Your Task⌗

Look at the image above and draw it independently using:

• goto(x, y)
• setheading(angle)
• forward(distance)
• penup()
• pendown()
• pensize()
• pencolor()

Use the Turtle boilerplate code provided earlier in this lecture.

Important Coordinates (Use These!)⌗

To help you draw the pine tree, use these exact coordinates:

• Top of triangle → goto(0, 80)
• Bottom‑right → goto(60, -20)
• Bottom‑left → goto(-60, -20)
• Trunk start → goto(0, -20)

These points will help you draw the triangle and trunk in the correct place.

Create Your Own File⌗

Create a new Python file in VS Code named:

turtle_class4_independent.py

Inside that file, use the boilerplate and write your pine‑tree code in the section marked:

# --- ENTER YOUR CODE HERE ---

Submission Instructions⌗

Submit your work in Google Classroom by:

1. Creating a Google Doc
2. Pasting your code into the document
3. Adding a screenshot of the output window showing your drawing
4. Turn in the Google Doc to the assignment titled In‑Class Exercise 4