4th of July Yard Sign Cutouts - Fireworks Patriotic Heart Memorial Day Independence Day Yard Decor, 4th of July Yard Sign With Metal Stakes. Economical and durable, our Coroplast Yard Signs are a staple of outdoor advertising. This Memorial Day Yard Signs with Stakes full color direct printed graphics are vertically fluted for use with a Stakes. Coroplast is typically used for yard, parking, real estate, and election signs. They are waterproof.