Art Piece is an item in Broken Age.
Obtaining
In the Lumberjack's House, the art piece hangs above the fireplace. After you look at it, talk to Curtis about it. Choose a few of the dialogue options and then complement the art on matching Curtis' decor. He will become offended and let you take it away.
Using
Inside the Dead Eye Pyramid, use the art piece inside the socket that matches its shape. Then tap it to free Alex.