That would be appreciated. It'd be nice to see the minimal complexity needed for something like a local credit union that managed customer savings and checking accounts, as well as home and car loans.
More ambitious would be a central banking app, in particular how does double-entry accounting work when a central bank (i.e. the Fed) is doing 'quantitative easing' and using their helicopter money to buy up Treasury bonds and mortgage-backed securities in order to keep major banks and government solvent? What's the private bank's balance sheet look like when they use the central bank money for stock buy-backs instead of for increasing commercial lending?
For example, the Fed says it's unloading the mortgage-backed securities it bought up in 2008-2009. That's got to be some convoluted accounting:
https://www.marketplace.org/2022/06/02/why-the-federal-reser...