Technology challenge
Computers & Computational Thinking
Work at your pace. Take a break between stages; there is no countdown.
You need: paper, a pencil and this lab. A helper is welcome for reading and discussion.Connect to what you know
Computers follow instructions. Now become the person who writes them clearly.
Understand it, step by step
- 1
An algorithm is an ordered set of steps. “Draw a square” describes a goal; a drawing machine also needs directions and distances.
- 2
Our pen starts at the marked point. Each arrow draws one unit in an absolute direction: up always means towards the top of the page. Nothing moves until you press Run.
- 3
Trace the steps with your finger before running. If the result differs from the goal, find the first step where it goes wrong. Changing that step is debugging.
For a 1-unit square: ↑ → ↓ ←. Each side has one unit and the last step returns to the start. ↑ → ↓ → fails: its last arrow travels away from the start.
Pause and predict
How many arrows make a square with sides of 2 units?