Laravel Solution: Laravel 5 using OR condition with BETWEEN

Hi can anyone help me building below query in laravel Eloquent i am really confuse in using or condition with between

SELECT * FROM tbl WHERE
existing_start BETWEEN $newSTart AND $newEnd OR
$newStart BETWEEN existing_start AND existing_end

i tried using like

whereBetween('existing_start',[$newSTart,$newEnd])

but have no idea how to using OR

Laravel Solution