A flat (short for scenery flat) or coulisse is a flat piece of theatrical scenery which is painted and positioned on stage so as to give the appearance of buildings or other background. Flats can be soft covered (covered with cloth such as muslin) or hard covered (covered with decorative plywood such as luan). Soft-covered flats have changed little from their origin in the Italian Renaissance. Flats with a frame that places the width of the lumber parallel to the face are called "Broadway" or "stage" flats. Hard-covered flats with a frame that is perpendicular to the paint surface are referred to as "Hollywood" or "studio" flats. Usually flats are built in standard sizes of , , or tall so that walls or other scenery may easily be constructed, and so that flats may be stored and reused for subsequent productions. Often affixed to battens flown in from the fly tower or loft for the scenes in which they are used, they may also be stored at the sides of the stage, called wings, and braced to the floor when in use for an entire performance. Flat construction Parts of a flat Rails (or plates) are the top and bottom framing members of a flat. Rails run the full width of the flat (, for a , flat). Stiles (or studs) are the vertical members of the frame. The length of the stiles is the full height of the flat, minus the combined width of the rails (, for a , flat constructed of , rails). Toggles are horizontal cross pieces that run between the stiles or studs. The number and placement of toggles depends on the type of flat. The length of the toggles is the total width of the flat minus the combined width of the stiles (, for a , soft-cover flat constructed of , stiles). Corner blocks are used to join the corners of a soft-cover flat. They are normally made of plywood, and are triangles with corners of 45°, 45°, and 90°. They are most often made by ripping the plywood at and then mitering it at 45 degree angles to create triangles with legs. Keystones join the toggles to the stiles of soft-cover flats. They are long, and normally rip sawn to the same width as the toggles (usually ) on one end, and on the other, forming a shape similar to the keystone