array(
	0 => array(
		"lenght" => 8
	),
	1 => array(
		"lenght" => 10
	),
	2 => array(
		"lenght" => 5
	),
	3 => array(
		"lenght" => 3
	),
	4 => array(
		"lenght" => 12
	),
	5 => array(
		"lenght" => 8
	),
	6 => array(
		"lenght" => 5
	)
)

to

array(
	0 => array(
		0 => array(
			"lenght" => 8
		),
		1 => array(
			"lenght" => 10
		),
	),
	1 => array(
		0 => array(
			"lenght" => 5
		),
		2 => array(
			"lenght" => 3
		),
		3 => array(
			"lenght" => 12
		),
	),
	2 = array(
		0 => array(
			"lenght" => 8
		),
		 => array(
			"lenght" => 5
		),
	)
)