Abstract: An electromagnetic indicator device which has a plurality of triangle-shaped vanes, asymmetrical in relation to the rotation axis, which are arranged on a plate in the form of a matrix. A polarization magnet is applied to the vane in the vincinity of the rotation axis. The movement of the rotably supported vanes from a first position to a second position is effected, as appropriate, by a permanently associated electromagnet fixed behind the plate. A network of bearing brackets is fixed on the plate, whereby each four bearing brackets form the corner points of a square.

Abstract: A shell structure is pivoted outwardly of a house trailer to enlarge the floor area. The shell structure can include three sides positioned over a cabin or portion of a cabin, and the shell structure is pivotal about a horizontal axis near the level of the floor of the cabin which is mounted on the trailer frame. When pivoted outwardly, a folding slidable or extensible roof can be positioned on the upper edges of the shell structure.