Just do a mk and run the resulting binary.  Rio works as normal,except that mid-clicking outside of any window brings up a menu withthe different virtual desktops listed. To my knowledge, this works just like p9p rio's virtual desktops. The new options: '-n' will enable "nostalgia mode", which for now emulates the 8½window border color and style. '-b 0xrrggbbFF' will set the background color to rrggbb.  The trailing'FF' does not appear to be important.  The default color is0x777777FF.