The arrow points in one direction.

FORBES: Investing in Biofuels or Biofools?

Along the trail, was a marker, an arrow pointing to the right direction (attributed to Brigham Young), to help keep the wagon trains on the right path.

FORBES: Say Good-Bye to Email?

If a change of direction is needed, the walking stick vibrates, and an arrow appears.

BBC: Fujitsu makes 'smart walking stick' to help elderly

You'll see the arrow pointing on a map where to go, but if you turn your head, that arrow doesn't swivel around to stay pointed in the right direction.

ENGADGET: Living with Google Glass, Day Two: Around the House

If time truly has an arrow, though, some of these shifts will occur at a different rate when going in one direction rather than the other.

ECONOMIST: The arrow of time