A Point Value Object

Point.php

<?php

final class Point
{
    private int $x;

    private int $y;

    public function __construct(int $x, int $y)
    {
        $this->x = $x;
        $this->y = $y;
    }

    public function add(self $point): self
    {
        return new Point($this->x + $point->x, $this->y + $point->y);
    }

    public function equals(self $point): bool
    {
        return ($this->x === $point->x) && ($this->y === $point->y);
    }

    public function __toString(): string
    {
        return "({$this->x}, {$this->y})";
    }
}

$p1 = new Point(1,1);
$p2 = new Point(1,-3);
$p3 = new Point(1,1);

$p4 = $p1->add($p2);
echo $p4 . "\n"; // (2, -2)
echo ($p1->equals($p4) ? 'equal' : 'different') . "\n"; // different
echo ($p1->equals($p2) ? 'equal' : 'different') . "\n"; // different
echo ($p1->equals($p3) ? 'equal' : 'different') . "\n"; // equal