'Boustrophedon means something like "as the ox turns." Today we write in stoichedon style, in which all the letters face the same direction, like soldiers standing in formation. Boustrophedon is based on an agricultural, not a military ideal:the writer writes as a farmer plows. Write to the end of the line, and then, rather than returning to the left side of the page, turn the letters to face the opposite direction and write from right to left. When you read boustrophedon, your eye follows a zig-zag across the page -- or the stone.
Have a look at this close-up of the engraving at Gortys and look at the way letters like "E," "K," and "S" face in adjacent lines: