Day shapes or day markers are mast head signals comprised of geometric shapes. These signals convey the status of a vessel on navigable waters during daylight hours. The four basic shapes of the markers are ball, cylinder, cone, and diamond. The day shapes are used alone or in combination to provide a range of status updates visible during the day and are intended to mimic the navigation light requirement during nightfall or poor visibility. Day shapes are required to be deployed from sunrise to sunset and are typically hung from a mast for ease of visibility from a distance.