<?php
class Car
{
    public string $color;
    public int $speed = 0;

    public function accelerate(int $amount): void
    {
        $this->speed += $amount;
    }
}

$first = new Car();
$first->color = "red";
$first->accelerate(30);

$second = new Car();
$second->color = "blue";

echo $first->color . " car at " . $first->speed;  // red car at 30
echo "\n";
echo $second->color . " car at " . $second->speed; // blue car at 0
?>