Online PHP editor | output for Abvpq

<?php //this seems to work as if there is 2 variables both a public static and a private static class foo{ public static $myvar = 99; //Uncommenting below leads to a Cannot redeclare foo::$myvar //public $myvar = 77; public function __construct(){ $this->myvar = 35; } public function printMyVar(){ echo '->printMyVar(): '.$this->myvar; } public function setMyVar($mv){ $this->myvar = $mv; } } echo "foo before creation: \n"; echo 'static: '.foo::$myvar: '.foo::$myvar."\n"; echo "Creating new instance of foo\n"; $foo = new foo(); echo 'instance: '.$foo->printMyVar(); echo "\n"; echo 'static foo::$myvar: '.foo::$myvar."\n"; $foo->setMyVar(33); echo "After setting $myvar to 33\n"; echo 'instance: '.$foo->printMyVar(); echo "\n"; echo 'static foo::$myvar: '.foo::$myvar."\n"; echo "Conclusion: when using \$this-> to change the value, it adds another non-static version rather than changing the static version";