Mission 4  ·  Hints

Zig-Zag Stairs

Open one hint at a time. Try it before you open the next.

Hint 1 — Think about it
A list is a row of boxes that grows. Every time the car makes a decision, drop a letter in the next box. When it finishes, read the boxes back. What would a mirrored maze give you?
Hint 2 — Which blocks to use
delete all of ( route )Start with an empty list.
add ( R ) to ( route )One letter per turn.
write ( route ) on the light matrixScrolls the list across the hub.
repeat until < color sensor sees green >Your S-Curve loop, unchanged.
Hint 3 — Plan in plain words
  1. Copy your Mission 3 program.
  2. Empty the list at the start.
  3. In each branch (right, left) add the matching letter.
  4. After the loop, write the list on the hub.

Watch out: Add the letter inside the branch that made the turn, or the list will be wrong. A dead end adds a U — there should be none here.

Playbook: Stop and look · The right-hand rule · Remember your route

← Challenge

Printable version: mission-4-hints.pdf