Parchment vs. Clay Tablet?
Lunar Calendar vs. Solar Calendar?
Already HDDVD vs. BluRay seems so old, but it's just another in a long list.
Gonna go with that time cuneiform flipped from up-down to left-right.
n the mid-3rd millennium BC, the direction of writing was changed to left-to-right in horizontal rows (rotating all of the pictographs 90° counter-clockwise in the process) and a new wedge-tipped stylus was introduced which was pushed into the clay, producing wedge-shaped ("cuneiform") signs; these two developments made writing quicker and easier. By adjusting the relative position of the tablet to the stylus, the writer could use a single tool to make a variety of impressions.
It's possible there was a conflict over pictographic representation in cave paintings but I don't know enough to comment.