Plan a route through a maze
Guide a robot through a 7 × 7 maze to its battery. Break the long route into short parts, find the block where a plan with a counting mistake breaks, and build the shortest plan.
Core concept
A big problem is easier when it is broken into small parts (decomposition); each part becomes a few steps, and a mistake in one part, such as one move too many, breaks the whole plan
Topic: Computational thinking
Long problems are easier in pieces. To cross a maze, you do not plan every step at once; you split the route into parts: “go up to the first gap”, “go right to the long corridor”, “go up again”. Each part becomes a few blocks: some moves, then a turn. This is called decomposition, and programmers use it for every big program. Pieces also make bugs easier to find: if the robot bumps into a wall, you check the part where it happened. One move too many in one part is enough to break the whole plan.
What you will learn
- Break a long route into parts and write each part as blocks.
- Find the part of a plan where it breaks, and fix it.
- Count the moves and turns a route needs.
- Find the shortest plan through the maze.
Before you start
- Know how the robot's move and turn blocks work (see “Help the robot reach the battery”).
Materials
- Squared paper to draw the maze and the route
Equipment
- None
Procedure
- Run the starting plan and find where it bumps into a wall.
- Fix it, or build your own plan, so the robot reaches the battery.
- Make the plan as short as you can.
- Answer the practice challenges.