Paul Vallas For Chicago Mayor 2023 Yard Sign, Coroplast 2023 Mayoral Election for Mayor of Chicago Paul Vallas 2023 Yard Sign with Metal H-Stake. Economical and durable, our Coroplast Yard Signs are a staple of outdoor advertising. This Paul Vallas For Mayor of Chicago Yard Sign Decoration full color direct printed graphics are vertically fluted for use with an H-Stake. Coroplast is typically used for yard, parking, real estate, and election signs. They are waterproof.