First of all, I would like to make clear that this in not a C programming question, but it has to do with it.
About a year a go I made a program in C that computes the day of the week of a particular date, after christ.
I wanted to have this program running, but not in a computer; instead, in a mechanical machine. With a little time, I solved the thing with 2 small concentric discs. The discs are marked with CENTURIES, YEARS, MONTHS, and DAYS. All you have to do is rotate the discs in a manner so that you can compute the day of the week by watching trought a little hole in one of them. Unfortunately, you can compute dates only and only if the date is between 1600 and 2000.
Now the question is: Would someone be interested in buying such a thing and hang it on the wall of his/her home?
I live in Mexico City, and no one here is interested in nowing the day of the week he or she was born, or when a particular date is Saturday or Sunday ????
But, maybe if I go to the piramids of Teotihuacan, and offer this thing to the foreing people that comes to my country to see something curious, maybe I would have some luck. What do you think ????