Polyptych Polyptych A polyptych ( ; Greek: "poly-" "many" and "ptychē" "fold") is a painting (usually panel painting) which is divided into sections, or panels. Specifically, a "diptych" is a two-part work of art; a "triptych" is a three-part work; a tetraptych or quadriptych has four parts; pentaptych five; hexaptych six; heptaptych (or septych in Latin) seven; and octaptych eight parts. Polyptychs typically display one "central" or "main" panel that is usually the largest of the attachments, while the other panels are called "side" panels, or "wings". Sometimes, as evident in the Ghent and Isenheim works, the hinged panels can be
Hinged expansion joint joints used in piping systems are restricted to pure angular rotation by its hinges. As a pair, hinged expansion joints will function together to absorb lateral deflection. Advantages of hinged expansion joints are that they are typically compact in size and structurally rigid. Hinged expansion joint A hinged expansion joint is a metallic assembly, that can rotate in a single plane, used to absorb changes resulting from piping thermal expansion or contraction. They include hinges, attached to the expansion joint ends with a pair of pins, which allow angular movement in a single plane, restrain the pressure thrust, and prevent