In 1986 a large stela was discovered at La Mojarra, in the Olmec area of the Central American isthmus. Although very little of the language is known, not even what people or date to ascribe it to, a few things are apparent.
The stela consists of 21 columns, which can be lettered A through U, of mostly rectangular symbols. From various clues, they have determined that the columns are in the following order. A is is the very center of the stela. A through L run from the middle to the left hand edge. Column M, however, is immediately to the right of A. M through U run from the middle to the right edge.
L K J I H G F E D C B A M N O P Q R S T U
Not only that, but individual symbols also point to the middle, so that duplicates from either side are mirror images of one another.
Schematically:
a symbol in column F: ))–.* would read *.–(( if placed in column P
Pictures and diagrams can be found in Andrew Robinson’s excellent Lost Languages.
I know of no parallel, so to speak, in any other writing.