6ix by 3hree (Six By Three) is a video compilation by Duran Duran released in 1989. There is currently no commercial DVD release available but the whole compilation was included as an extra on the 2010 DD Fan Club DVD release of 'Three To Get Ready'. The six videos of the title are from the bands' albums Notorious and Big Thing.
The intent of this release was similar to the Seven and the Ragged Tiger video EP "Dancing on the Valentine", mopping up an album's worth (or two albums in this case) of videos and getting them to market. However, the release of Decade a year later meant that most of the videos on both of these compilations were readily available on one release.
6ix by 3hree does include two videos not available on other compilations - "Meet El Presidente" and "Do You Believe in Shame?" - but they were included as extras on the CD/DVD special releases of Notorious and Big Thing respectively.