Abstract: A spherical junction element for composable display structures, comprising a body having at least one partially spherical outside surface, at least one flat outside surface intersecting the partially spherical surface, at least one slot in said partially spherical surface, which is perpendicular to at least one of the flat surfaces for fittingly receiving therein a plate like component member and for defining a base plane with at least one of the flat surfaces, a pin in the slot having a diameter less than the gap of the slot, and a reinforcing sleeve element pulled over the pin, the sleeve element being provided with two or more surface portions to engage the mating surface portions of the slot.