create a background image or layer for a square team schedule poster. The teams colors are forest/dark green, Columbia blue and white. This image will be used as the background for a football schedule laid over the open gritty/background space. The overall design is gritty and high-contrast, with textures and hard angle shapes that suggest wear and tear, giving it a rugged, competitive feel. make sure the entire background of the image is full of the gritty textures. --v 6.0 --ar 1:1