A movable supporting construction for placing on a floor, comprising a lower part and an upper part cooperating with said lower part, wherein the lower part is designed to rest on the floor and to assume a position that is determined by the condition of the floor, and the upper part has a first and a second position, wherein in the first position, the upper part is suspended freely above the lower part and in the second position, the upper part rests on the lower part maintaining a predetermined invariant position, wherein in the second position, the lower part and the upper part are in line contact, thereby determining a contact line that forms at least a portion of a closed line.