A panel with a working surface and four edges of which oppositely disposed pairs of edges have corresponding holding profiles so similar panels are connectable. Holding profiles of a first pair of edges are connectable by angular movement into interlocking relationship Holding profiles of a second pair of edges are hook elements, which are connectable to similar adjacent panels by joining movement provided a hook element is a separate vertical locking element projecting toward joining movement of the hook elements. During joining, the vertical locking element is movable out of the path of joining movement and when hooked, the hook elements are movable toward the joining movement by spring action. When dismantling, connected panels are unlockable from hooked and vertically locked condition by pivoting about an axis near the hooked edges and toward an unlocking position. The working surfaces, when unlocked, are less than 180° relative to each other.