The Two Fours

When I was a young boy, I had a brief discussion with my parents about writing the number four. Unlike the other numerals, there were two different ways to write a four. These we could call the "open four" and the "closed four". I was instructed to write the "open four" as the "closed four" was "old fashioned".

But I noticed that the page numbers of books were always the closed four, 4. Road signs everywhere always seem to use the closed four. Image from Google Street View.

Handwriting seems to be a mix of the closed and open fours. What gave a major boost to the open four was digital display technology, using lighting elements that can either be on or off. If seven elements are arranged in a square figure 8, any numeral can be displayed by which elements are on or off. This favors the open four.

But when computer and smart phone technology came along, it decisively shifted the balance back to the closed four. At this point the digital displays, as shown above, are all that is keeping the open four alive. We can expect that someday it will pass into history.