Diptych the title of works consisting of two paintings never actually connected, but intended to be hung close together as a pair, such as Andy Warhol’s "Marilyn Diptych" (1962) which is a modern pop culture icon. "Diptych" is also often used in reference to films or pieces of literature that form a complementary pair. When taken together, they are viewed as illuminating each other and comprising a distinct work of art from the individual parts. An example is the pair of Alan Ayckbourn plays, House and Garden. It is in this form that the mention of "diptychs" in early Christian literature
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