A method of producing a shaped element has been patented. The element is characterized so that a blank, intended to constitute the shaped element, is produced in plane form with an elongate shape containing a longitudinal and a transverse direction. The elongate shape also features two short and long sides, two ends and a central portion, where one end portion is given a width, which increases toward the blank’s short side. A cut-out is arranged in the other end portion, and the blank is folded double along a longitudinal centerline of the blank. The cut-out is also joined together and the joined parts are then folded up into a three-dimensional state.