This project was a wordpress plugin to handle selling sign letters.
There is lots of nuances to wordpress and I think this plugin found them all. The big thing this plugin did was make the process quick, very quick.
The typical approach to this was to make a product (e.g. Brass Letters) that had many variations. The "many" turned out to be thousands when expanding all the options of letters, size, color, finish, thickness, and then some. To speed this up the idea of using variations was completely abandoned. Instead the product would have all the attributes that the customer wanted with a price that the supplier wanted.
The plugin is still in use today and has filled thousands of orders.