Grandma's Intergalactic Taxi

Visible system / hidden curriculum

Build something clear enough to test.

What students build

A space map with three or more destinations
A controllable taxi
Arrival detection at each destination
Passenger pickup and delivery states
A completed-trip counter
A reset path after mistakes

What students learn

Coordinates
Movement
Distance
Sequences
Score
Boundaries
Debugging

What students need

Browser
Scratch editor
Keyboard

This is not a complete teacher-led recipe. The required systems define the project, but students may draw different maps, choose different controls, and solve arrival and dispatch logic in more than one correct way.

Computer Lab character

Mission, constraints, and several correct solutions.

This is not a complete teacher-led recipe. The required systems define the project, but students may draw different maps, choose different controls, and solve arrival and dispatch logic in more than one correct way.

Required systems

What must exist.

A space map with three or more destinations
A controllable taxi
Arrival detection at each destination
Passenger pickup and delivery states
A completed-trip counter
A reset path after mistakes

Suggested build order

One useful route through the problem.

Draw the map and record useful destination coordinates.
Place the taxi at a known start and build movement controls.
Detect arrival at one station before adding the others.
Create pickup and delivery states for one passenger.
Track completed trips and reset the current request.
Test boundaries, wrong destinations, and repeated arrivals.

Checkpoints

Evidence that the system is becoming reliable.

1The taxi starts from a known position.
2At least three destinations have distinct locations.
3Pickup and delivery are different states.
4A trip cannot score repeatedly without a new request.
5The student can explain one route using x and y changes.

Challenge cards

Change the lesson idea without repeating its first form.

Choose one card, combine compatible cards, or propose an equivalent challenge. More than one implementation can satisfy the mission.

CHALLENGE 1

Fuel decreases with movement.

CHALLENGE 2

Passenger destinations are randomized.

CHALLENGE 3

A wrong station costs time.

CHALLENGE 4

An asteroid zone changes the route.

CHALLENGE 5

Coordinates appear as a navigation display.

CHALLENGE 6

Create a shortest-route challenge.

Test it

Try the edges, not only the easy success.

Can the student demonstrate the taxi starts from a known position.?
Can the student demonstrate at least three destinations have distinct locations.?
Can the student demonstrate pickup and delivery are different states.?
Can the student demonstrate a trip cannot score repeatedly without a new request.?
Can the student demonstrate the student can explain one route using x and y changes.?

Common mistakes

Read the clues before changing code.

Testing only the easiest successful path.
Changing several systems before retesting.
Resetting only part of the project state.

Improve it

Preserve the core system while changing the project.

Fuel decreases with movement.
Passenger destinations are randomized.
A wrong station costs time.
An asteroid zone changes the route.
Coordinates appear as a navigation display.
Create a shortest-route challenge.

Challenge levels

Choose meaningful difficulty.

LEVEL 1

Builder

Complete and explain the required systems.

LEVEL 2

Inventor

Choose one challenge card and test the result.

LEVEL 3

Boss Level

Add a dispatch system that gives destinations in coordinate form, such as 'Pickup requested near x: 140, y: -80.' The player must read the request and navigate without a flashing destination marker.

Show-teacher checkpoint

Demonstrate the working decisions.

Three destinations on a coordinate map
A complete pickup and delivery
A trip counter that changes once per delivery
Recovery from a wrong route or mistake
One independently chosen challenge card

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