<?php
interface Colorful {
    public function color(): string;
}

enum Suit implements Colorful {
    case Hearts;
    case Diamonds;
    case Clubs;
    case Spades;

    public function color(): string {
        return match ($this) {
            self::Hearts, self::Diamonds => 'Red',
            self::Clubs, self::Spades => 'Black',
        };
    }
}

function main()
{
    echo Suit::Hearts->color() . "\n";
    echo Suit::Diamonds->color() . "\n";
    echo Suit::Clubs->color() . "\n";
    echo Suit::Spades->color() . "\n";
}