First of all, let's write an empty Vue instance that we will fill:
new Vue ({ el: '#app' })
You will need some material to work with; by this, I mean a whole lot of animals to classify. You can copy maybe only a part of this code in your Vue instance data, but to give you some inspiration, here it comes, the longest listing in this whole book:
data: { living: { animals: { invertebrates: { crab: null, bee: null, ant: null }, vertebrates: { fish: { shark: null }, mammals: { rabbit: null, rat: null } } }, plants: { flowering: { maize: null, paddy: null }, 'non-flowering': { algae: { seaweed: null, spirogyra: null }, fungi: { yeast: null, mushroom: null }, moss: null, fern: null } } } 
