PART OF CHILD'S DESIGNER SET

A hollow structural element for assembling a structure, has a hollow body part having an open side and being provided with means for connecting the body part with another structural element, and a cover insertable in the body part through the open side thereof. The cover is provided with at least one connecting element for connecting the same with a further structural element. The connecting element projects outwardly beyond a side margin of the cover and thereby forms a stop preventing the cover from excessive movement inwardly of the open side of the body part. Two such connecting elements may be arranged on the cover. The body part and the cover may be cup-shaped. The connecting means of the body part may be formed as undercut grooves and elongated undercut members. The connecting elements of the cover may also be formed as elongated undercut members.