Making it

Build Your Own Animal Game

The core idea can be built with a small decision tree, a console input loop and a way to save the tree locally.

Think of an animal A small interactive site about a tiny learning game from BASIC and microcomputer culture.

A simple Animal remake is a good vanilla JavaScript project because the rules are clear and the data structure is small. You do not need a server, a database or a framework unless you want shared online brains.

The browser version on this site uses three main ingredients: a tree object, a mode-based input loop, and local browser storage.

1. Represent the brain as a tree

const brain = {
  type: 'question',
  text: 'Does it swim?',
  yes: { type: 'animal', text: 'fish' },
  no: { type: 'animal', text: 'bird' }
};

Question nodes have yes and no branches. Animal nodes are leaves.

2. Walk through the tree

When the current node is a question, ask it and follow the branch matching the user’s answer. When the current node is an animal, make a guess.

if (node.type === 'question') {
  node = answer === 'yes' ? node.yes : node.no;
} else {
  guess(node.text);
}

3. Replace a wrong guess with a new question

When the program guesses incorrectly, keep the old animal, ask for the new animal, ask for a distinguishing question, and then replace the old animal node with a question node.

currentNode.type = 'question';
currentNode.text = newQuestion;
currentNode.yes = newAnimalNode;
currentNode.no = oldAnimalNode;

4. Save locally

For a static site, localStorage is enough:

localStorage.setItem('animalBrain', JSON.stringify(brain));
const saved = JSON.parse(localStorage.getItem('animalBrain'));

That saves the learned brain in this browser. Export/import buttons can turn that same JSON into a user-controlled save file.

What to avoid at first

Do not start by building a full BASIC interpreter, a ZX81 emulator or a multi-user shared brain. The appeal of Animal is that the core idea is visible, so a first version should stay small, explainable and self-contained.