Each release of Debian has a shiny new theme, which is visible on the boot screen, the login screen and, most prominently, on the desktop wallpaper. Debian plans to next release, Trixie, next year. As ever, we need your help in creating its theme! You...
I always keep close track of these contests, it's fun to take a look at all the different concepts. Though IIRC only Juliette Taka (who designed the themes for 8, 9, and 11) even submitted a theme last time. She's great, and Emerald is great, but I hope this post gets someone even better involved with the artwork.