Head or Tail

http://www.otuzoyun.com/rotator/

Cihan Altay’s Rotator typeface presents the digits 0-9 whether it’s right side up or upside down.

So this equation:

http://www.otuzoyun.com/rotator/

… can be inverted to make this one:

http://www.otuzoyun.com/rotator/

Both are valid.

(Thanks, Lorenzo.)