By EdCaptain editorial desk · Published
The picture was supposed to have a mouth below its eyes. The drawing has a mouth above them. Before anyone reaches for an eraser, there is a useful question to ask: what did the instructions actually say?
This screen-free debugging activity is for ages 7–11. Children follow a short drawing recipe, compare the result with a visible target and repair one instruction. The drawing is evidence of what happened, rather than something to mark as good or bad. You need paper and pencils, not an app or a coding kit.
Barefoot Computing’s 2D Shape Drawing Debugging activity uses errors in drawing instructions as a way to explore debugging. Its Crazy Character Algorithms resource explains an algorithm as a precise sequence of instructions or rules for a task. The original family example below applies those ideas to one small paper challenge.
Set up a fair problem
Gather plain paper, pencils or crayons and four large pieces of paper for instruction cards. Fold sheets into sections if you prefer not to cut them. Use age-appropriate tools and keep loose pieces away from younger children who might mouth them.
On a separate sheet, draw a simple target: a large square face, two circular eyes side by side in its upper half, a short straight mouth below the eyes, and a short antenna rising from the top edge. Keep it visible throughout. Exact size and neatness will not be part of the check.
Make these four instruction cards:
- Draw a large square near the centre of the page.
- Inside the square’s upper half, draw two circles side by side for eyes.
- Inside the square, draw a short straight mouth above the eyes.
- From the middle of the square’s top edge, draw a short antenna pointing upwards.
Tell your child openly: “One instruction does not match the target. We’ll try the recipe, find where it changes the result, and repair it.” This is a shared puzzle, not a trick designed to catch someone out.
Run it, inspect it, change it
- Agree what counts as matching. Both drawings need the same four features in the stated positions. Wobbly circles and different-sized squares are fine. Check that your child understands the position words before beginning.
- Follow one card at a time. Keep the cards in order and leave each completed card visible. An adult can read aloud. If a sentence is unclear, pause and clarify it rather than guessing silently.
- Compare without correcting the picture. Place the result beside the target. Ask, “Which feature is in a different place?” Let the child point or explain. Notice what already matches, too.
- Trace the difference back. Read through the cards again, following each feature on the page. At the mouth instruction, compare “above” with the target. Ask which word would make this step fit the agreed goal.
- Repair and retest. Replace “above” with “below”, keeping the original card nearby. Begin on a fresh sheet and run all four steps again. Compare the new result with the target using the same checks.
If your child spots the error before drawing, accept that. Ask them to explain what the original wording would produce, then test the repaired version. They do not need to complete an unwanted drawing to prove they noticed.
Find the problem in the recipe, not the person
Use language such as “That instruction placed the mouth here” or “Our new wording changed the result.” Avoid “You should have known what I meant.” In this round, following the faulty card correctly can produce the wrong arrangement.
If the child quietly draws the intended mouth instead, you can say, “You used the target to repair it in your head. Could we put that repair into the card so someone else can use it?” That makes their reasoning available without treating initiative as disobedience.
Keep this literal-instruction game separate from real-life safety. Children can always question, refuse or stop an unsafe or uncomfortable instruction. Nobody needs a blindfold, a robot costume or a physical obstacle course.
Offer another round only if wanted
Switch roles: the child makes a new target and a short recipe for you to try. Agree to include only one mismatch at first, tell the other player it is there, and use shapes they can comfortably recognise. Avoid hiding essential information or changing the target halfway through.
A different challenge is an unclear sentence rather than an incorrect one. “Put the star next to the circle” may need “on the left” or “on the right”. Mark that as missing information: several interpretations can be reasonable. Ask the designer which result they intend before rewriting it.
For a related activity centred on comparing routes rather than debugging a drawing, see the fictional map-route game.
Keep the reasoning accessible
Ages 7–9: Use this single-error example, read each card aloud and let the child point to the changed word. You can draw while they direct you. Stop after one repair if that is enough.
Ages 10–11: Invite a written prediction before the test: “This step will put the mouth…” Then ask them to explain why the replacement wording meets the goal. They can keep a two-column record of the original instruction and the repair; a long report is unnecessary.
At either age, enlarge the cards, use high contrast and allow extra processing time. Offer familiar shape outlines to trace, or let the child direct a partner using speech, signing or their usual communication aid. If visual comparison is inaccessible, describe the target and result in agreed positional language, or use large tactile shapes with adult preparation. Keep the thinking task separate from handwriting or drawing accuracy.
Finish by naming the useful change
Ask one optional question: “What showed us which step to change?” A concrete answer might be pointing from the mouth to the word “above”. Save both attempts only if the child wants them.
If frustration takes over, pause. The guide to supporting tinkering when a plan fails offers ways to help without taking over. This activity provides a chance to inspect and revise a sequence; it is not a test of intelligence or a promise of improved school performance.
Sources and further reading
- Barefoot Computing: 2D Shape Drawing Debugging — the established unplugged approach of finding and correcting errors in drawing algorithms.
- Barefoot Computing: Crazy Character Algorithms — precise instructions and improving a drawing algorithm.
