<!DOCTYPE html>
<html>
<body>
<?php
interface Machine {
public function activate();
public function deactivate();
public function isActive();
}
class Kettle implements Machine {
private $isOn = false;
public function activate() {
$this->isOn = true;
}
public function deactivate() {
$this->isOn = false;
}
public function isActive() {
return $this->isOn;
}
}
