This is quite the update - very sleek. My favorite new feature is the "show on hover". Just put your mouse where the icons should be and the appear like magic!
It really cleans up an already improved menu bar in macOS Big Sur.
We use HelpDocs.io (love it) and they have a "set article to go stale" option. I haven't used it, but it seems like a nice reminder to re-evaluate or delete the page.
What a great project. I have a very similar book (1800 Mechanical Movements, Devices, and Appliances) and have a blast flipping through it. It is great to see the illustrations come alive. Great great job!
Back in the 1920s/30s when sales tax was introduced, companies had to decide whether to include the tax in the item's price, eat the cost, or pass it along to the customers. As we are all painfully aware, it was passed along to the consumers. This is a really creative way of combining credit/store card rewards with sales tax in consumer's minds. Of course money is fungible, so it doesn't matter if the reward is covering sales tax or just a fixed percent (although the later could be higher than most fixed percents depending on state). Regardless, an interesting experiment.