←
Build the decisionSaved automatically
Easy · Grade 14. Build Your Own Strategy

Create a custom cornering function and use rules to navigate the Snake Corridor.

Scenario

The Snake Corridor winds back and forth. Repeating turn-then-step actions manually makes rules repetitive.

Problem statement

The Snake Corridor is an 11x11 winding path that requires the robot to repeatedly turn into open side passages and step forward.

Writing separate turn and step rules over and over makes your intelligence cluttered. Instead, use the Functions tab to build a custom reusable action: a sequence that turns left and takes a step in one package.

Rules decide when to execute the function, while the function handles the fixed sequence of actions.

The starting brain unlocks custom Functions. Build a new function (e.g. `turn-left-and-step`) that sequences `pivot-left` followed by `step`.

Your rules then call this custom function whenever the left side is open, keeping your brain clean and modular.

What this teaches

Separate decision logic from action sequences: rules choose when to run a function, and functions package multi-step moves.

Scroll down to build and test your solution.

Active controller

Apply & Run executes only the selected controller.

How a rule works

A rule has two parts:

WHEN <something is true> → DO <this action>

  • WHEN is a question about what is happening right now. For example: "Is it raining?" or "Is there a wall ahead?"
  • DO is what happens when the answer is yes.
  • The simulation runs one step at a time.
  • On each step, the rules are checked from top to bottom.
  • The first rule that is true wins. The rules below it are skipped for that step.
  • To change which rule wins, move it up or down the list.
  • If no rule is true, nothing happens on that step.
  • Some actions have more than one step, like "turn right, then move". You build these in the Functions tab.
  • Once a multi-step action starts, it finishes all its steps before the rules are checked again. It only stops early if the next step is not safe.
See an example

Two rules for deciding about an umbrella:

1  WHEN isRaining  → take an umbrella
2  WHEN always     → leave the umbrella at home
  • It is raining. Rule 1 is true, so you take an umbrella. Rule 2 is skipped.
  • It is sunny. Rule 1 is false, so rule 2 is checked next. Rule 2 is always true, so you leave the umbrella at home.
  • Order matters. If rule 2 were on top, it would be true every day, and you would never take an umbrella.

Rule folders

Categorise cards without changing their global execution order.

No rules yet. Nothing will happen until you add at least one rule.