The state of Texas on the team's helmet was replaced by an arrowhead design originally sketched by Lamar Hunt on a napkin. Hunt's inspiration for the interlocking "KC" design was the "SF" inside of an oval on the San Francisco 49ers helmets. Unlike the 49ers' logo, Kansas City's overlapping initials appear inside a white arrowhead instead of an oval and are surrounded by a thin black outline. From 1960 to 1973, the Chiefs had grey facemask bars on their helmets, but changed to white facemasks in 1974, making them one of the first teams (alongside the San Diego Chargers, who introduced a yellow facemask that same year) in the NFL to use a non-gray facemask. The Chiefs' uniform design has essentially remained the same throughout the club's history. It consists of a red helmet, and either red or white jerseys with the opposite color numbers and names. White pants were used with both jerseys from 1960 to 1967 and 1989 to 1999. Beginning in 2009, during the Pioli/Haley era, the team has alternated between white and red pants for road games during the season. Prior to September 15, 2013, the Chiefs always wore white pants with their red jerseys. The Chiefs have never worn an alternate jersey in a game, although custom jerseys are sold for retail. The Chiefs wore their white jerseys with white pants at home for the 2006 season opener against the Cincinnati Bengals. The logic behind the uniform selection that day was that the Bengals would be forced to wear their black uniforms on a day that forecasted for steamy temperatures. The only other time the Chiefs wore white at home was throughout the 1980 season under Marv Levy. In 2007, the Kansas City Chiefs honored Lamar Hunt and the AFL with a special patch. It features the AFL's logo from the 1960s with Hunt's "LH" initials inside the football. In 2008, the patch became permanently affixed to the left chest of both Kansas City's home and away jerseys. In select games for the 2009 season, the Chiefs, as well as the other founding teams of the American Football League, wore "throwback" uniforms to celebrate the AFL's 50th anniversary. For the first time in team history, the Chiefs wore their red jersey with red pants forming an all red combo in their home opener against the Dallas Cowboys on September 15, 2013. Their all red uniforms are now an official uniform combination and has been used multiple times since. It is commonly used for prime time games at home.