HD Wallpaper: Abstract Squares
Rashad Mohammed is the artist who created and from his courtesy the image can be downloaded under CC By-Nc license. Here's optimized for use in desktop background and homescreen phone.
Widescreen Desktop / Macbook (Retina): 2880x1800 (fits on: 2560x1600, 1920x1200, 1440x900)
Samsung Galaxy Tab & iPad: 1800x1800 (compatible with many tablets)
HTC, Samsung Galaxy & iPhone: 1080x1920 (compatible with many phones)