Bug explanation.

// An array is an ordered list of items, with a starting index of 0.
var array = [];

// foo.push(bar) adds item bar to the end of array foo.
array.push('cat');
array.push('dog');
array.push('bird');

console.log(array.length); // 3
console.log(array[0]); // cat
console.log(array[2]); // bird
array.push('fish'); // Push 'fish' to 'array'
console.log(array.length); // 4

// Empty the array-delete everything in it.
array = [];

console.log(array.length); // 0
array = ['cat', 'dog', 'bird', 'fish']; // Same as push, except all at once.
console.log(array.length); // 4

// A multidimensional array is an array with an array.
// Rather than a single item at each index, there is an array at each index.

// Same as above, except each array item is an array.
array = [
    ['cat', 'dog', 'bird', 'fish'],
    ['apple', 'orange', 'melon', 'pear'],
    ['blue', 'green', 'red', 'yellow']
];

console.log(array[0][1]); // dog
console.log(array.length); // 3
console.log(array[1].length); // 4
console.log(array[2][2]); // red
console.log(array.[2][2].length); // 3 (3 characters in 'red')

// Every language, programming or spoken, is different.
// I mistakenly believed that a multidimensional array had to be declared as such.
// So I declared:
array = [[]];
// This declared an empty array, and added an empty array as the first element.