<?php
    class A {
		private $containigObject;
		public function __construct($containigObject){
		$this->containigObject = $containigObject;
		}
		public function functionThatAccessOutsideObject(){
		//...
		$this->containgObject->b = 2;
		//...
		}
	}
 
    class B {
		public $b = 1;
		public function someFunction(){
		//...
		$a = new A($this);
		$a->functionThatAccessOutsideObject();
		//...
		}
    }
 
    $b = new B();
    $b->someFunction();
?>

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