RISC OS by Andy C.

A simple persona resembling RISC OS' default theme; works well on Linux with the Gtk theme at <a href="https://prod.outgoing.prod.webservices.mozgcp.net/v1/3267238d0b9cf094dd8c668395a18a2091a7e1e88f17f6bad88f217d037126dd/http%3A//ubuntu-art.org/content/show.php/RiscOS%3Fcontent=128771" rel="nofollow">http://ubuntu-art.org/content/show.php/RiscOS?content=128771</a>. The image used is licensed under the GPL.