Boustrophedon (from Greek for ox-turning ) is writing that proceeds in one direction in one line (such as from left to right) and then in the reverse direction in the next line (such as from right to left). Some ancient languages, including one form of ancient Greek (650 BC), were written this way. The term derives from the way one would plow land with an ox, turning the ox back in the other direction at the end of a row. (It could be argued that boustrophedon is a more efficient way to both write and read, especially if your lines are very long.)
Some types of printers and their software print in this fashion (although the results, of course, are lines that are read in only one direction).