Circle of Mirrors

The Circle of Mirrors, also called a dimension cannon by Rose Tyler, was a time travel device created by the alternate UNIT of Donna's World, harnessing the power of the Tenth Doctor's salvaged TARDIS. It allowed Donna Noble to see the invisible Time Beetle on her back and to go back in time and turn left. (TV: Turn Left)
 * Theodore Maxtible also used mirrors and static electricity to achieve time travel. (TV: The Evil of the Daleks) Using a circle of mirrors on Deva Loka, the Fifth Doctor trapped and defeated the Mara. (TV: Kinda)