Rainbow colored polka dots on a white background. The offset rows form diagonals of each color: violet, indigo, blue, green, yellow, orange, and red.
Technically, the background is not white, it's actually transparent. That means you can change it. Just click the "Customize it" button, then click the "Edit" drop-down menu in the sidebar, click "Background," and select your color. When you're done, click "Add to cart" to purchase your customized design.