Befreak

Befreak is a purely reversible programming language, by virtue of the fact that every instruction is reversible. This means it is impossible to destroy data in any way. Befreak seems to have been invented by Brent Kerby and Hilton Campbell.

In form, Befreak is two-dimensional and takes after Befunge.

External resources

 * Befreak website
 * Befreak implemented in K