Abstract: A panel system comprises at least one bi-fold panel assembly (2, 3) of two panels hinged together along one edge (18) of each so as to be foldable thereabout, with at least one edge (20, 22, 24, 26) of the bi-fold panel assembly (2, 3) supported by a hinge device (30, 32, 34, 36) comprising two parallel pivot supports spaced apart in a plane orthogonal to pivot axes thereof, and a connecting link for in-situ connection therebetween. Hence the bi-fold panel assembly (2, 3) can be optionally connected in-situ by the connecting link to thereby obtain optional configurations of the panel system.