Learning · Parent guide
CSEdWeek 2026: An Unplugged Algorithm Grid Game
The robot turns right exactly as instructed—and misses the target. Was the robot wrong, or was the algorithm unclear? Trace each instruction instead of guessing from the final position.
Original BananaLearn guide · 2 November 2026
On a phone, swipe across the illustration to read every label.
Confirmed dates and an independent activity
Computer Science Education Week runs 7–13 December 2026, as confirmed in CSTA Washington’s dated 2026 announcement. This independent BananaLearn paper activity is not that organisation’s contest entry, campaign material or official partner programme. Local events and eligibility have their own rules.
The purpose is to practise precise instructions, orientation, tracing and debugging without a device. It does not use an AI model or claim that following a short route explains every part of computer science. It is suitable for roughly ages 9–14 with simpler or harder variants.
Prepare the original grid
Draw a four-by-four grid. Number rows 1–4 from top to bottom and columns 1–4 from left to right. The start is row 1, column 1, facing right. The target is row 3, column 4. Mark row 2, column 2 as blocked. These are grid addresses, not a Cartesian graph whose vertical axis increases upward.
Use a small paper arrow as the robot and a written command list. Allow about 30 minutes: 5 for rules, 5 for a first plan, 8 for tracing, 7 for debugging and 5 for a revision record. No outdoor activity or physical obstacle course is needed.
Define what each command does
Forward means move one square in the direction the robot currently faces. Right means turn 90° clockwise without changing squares. Left means turn 90° anticlockwise without changing squares. Stop if a forward command would leave the grid or enter the blocked square.
A turn is not a diagonal move or a step sideways. The facing direction is part of the robot’s state. If two people use different meanings for right, they can follow the same written list and reach different places. Agree the command definitions before judging an algorithm.
On a phone, swipe across the illustration to read every label.
Trace a complete working route
One working list is Forward, Forward, Right, Forward, Forward, Left, Forward. The first two moves reach row 1, column 3, still facing right. Right changes the facing to down. Two more forward moves reach row 3, column 3. Left changes the facing to right; the last forward reaches row 3, column 4.
This route uses five forward moves and two turns, seven commands in the expanded list. It avoids the blocked square at row 2, column 2. Other valid routes may exist. A different route is not wrong merely because it differs from the example.
Debug with a state record
After every command, record row, column and facing direction. If the result differs from the intended route, find the first state where the trace diverges. For example, omitting the right turn after the first two moves sends the next forward step to row 1, column 4 rather than row 2, column 3.
Do not repair the final position by secretly picking up the robot and moving it. Change the written command list, reset to the original start and trace again. A reproducible correction is stronger evidence than a route performed differently each time.
Introduce a repeat carefully
The first two forwards can be written Repeat 2 times: Forward. The next pair can use the same structure after the right turn. A compact description still expands to the same individual moves when executed.
Be clear whether a question counts written instruction lines, commands after expansion or forward moves only. These totals differ. In this activity, the working expanded route has seven commands and five forward moves. A shorter-looking list is not automatically a shorter travelled path.
Change one constraint for an extension
Move the target or add one blocked square and ask whether the original list still works. Keep the command rules unchanged so the learner can identify what the new constraint affects. For an easier version, remove the blocked square and start with a two-move route.
An extension can compare two valid algorithms by forward moves, turns or clarity. Do not claim the example is globally optimal without checking all relevant alternatives and the chosen cost definition. The aim is transparent reasoning about a small specified system.
Connect the result to clear everyday instructions
Ask the learner to explain how a precise starting state, explicit commands and a trace make a plan testable. Similar care helps with recipes, Maths methods and instructions, although those real tasks have their own extra conditions.
The record below preserves the original plan, first error, revision and retest. CSEdWeek supplies a timely opportunity to try the task; it does not establish measured search interest or a guaranteed learning outcome. All route examples and diagrams are original BananaLearn work.
Trace and debug record
Copy this record into a notebook. Fill each blank using your own example or the activity above.
On a phone, swipe across a wide table to see every column.
| Step | Command | Row, column | Facing |
|---|---|---|---|
| Start | None | 1,1 | Right |
| 1–2 | Forward twice | ___ | ___ |
| 3 | Right | ___ | ___ |
| 4–5 | Forward twice | ___ | ___ |
| 6–7 | Left, Forward | ___ | ___ |
| Revision and retest | ___ | ___ | ___ |
10 questions with explained answers
Try each question first. Open the explanation to check your reasoning. These are original BananaLearn questions, not official exam questions.
What are the verified 2026 dates used here?
Check answer and reasoning
7–13 December.
CSTA Washington’s 2026 announcement supplies the calendar evidence.Where does the robot start?
Check answer and reasoning
Row 1, column 1, facing right.
Position and orientation are both part of the starting state.Does Right move the robot into another square?
Check answer and reasoning
No.
It turns 90° clockwise on the same square.Where is the robot after the first two forwards?
Check answer and reasoning
Row 1, column 3, facing right.
Each forward moves one column right from the stated start.After the following Right, which direction does it face?
Check answer and reasoning
Down.
A clockwise quarter-turn from right points down.Where do the next two forwards lead?
Check answer and reasoning
Row 3, column 3.
The robot moves down two rows, keeping column 3.How many forwards are in the complete example?
Check answer and reasoning
Five.
Two before the right turn, two after it and one final move.How many expanded commands including turns?
Check answer and reasoning
Seven.
Five forward moves plus one right and one left turn.Does the example enter row 2, column 2?
Check answer and reasoning
No.
Its downward leg stays in column 3.How should a bug be repaired?
Check answer and reasoning
Change the written list, reset and trace again.
Moving the robot secretly would not test the revised algorithm.
Choose your next learning step
- Understand the separate curriculum context
- Connect a rule with its output
- Compare a different coordinate convention
Explore BananaLearn games, learning resources and tutoring. Maths is our priority; English and Science tutoring are also available. Share your current schoolwork when checking teaching fit.
Sources and scope
Explanations, activities, diagrams and practice are original BananaLearn work. Class labels suggest a learning level; school sequences and current textbook editions can differ. Sources checked 2 November 2026.
How we prepare guides · Report a correction
Share the complete guide: https://bananalearn.com/learn/computer-science-education-week-2026-grid-game.html