PlaidMaker is an online tool for making plaid gifs and plaid patterns. Pick the colors you want for your plaid image and then specify how many “threads” (columns or rows) you want. The images, when repeated make for great desktop backgrounds or repeating background images for websites. You can see one of the plaids in use at twitter.com/seanconaty.

For colors, you can put in any hexidecimal color value. Common plaid colors are red, green, blue, black, pink, purple, orange or a combination of them all.

For information on how to make repeating background images using CSS, you can find it at w3schools.