Hey! Here's a thing: so I play #pokechill and I've noticed that Flutter Mane looks like Misdreavus, so I researched and found that Flutter Mane is the ancient ancestor of Misdreavus. I've written this in a JavaScript logic gate:
The Lineage Logic
let m = "Volcarona"; // modern
let p = "Slither Wing"; // past
let f = "Iron Moth"; // future

if (m.visuals === p.visuals) {
console.log(`${p} is the Ancient Kin of ${m}`); // Result: Slither Wing is past version of Volcarona
}

if (f.visuals === m.visuals && f.visuals === p.visuals) {
console.log(`${f} is the Future Relative`); // Result: Iron Moth = future relative
}

(Replace Iron Moth, Volcarona and Slither Wing as needed, that's another realisation I had)