[svat]

There's another very nice description, with useful pictures, by Martin Blais (as part of the documentation of Beancount) at https://beancount.github.io/docs/the_double_entry_counting_m... (example picture that I would say is the heart of the idea: https://beancount.github.io/docs/the_double_entry_counting_m... )

Another one, with completely different graphs, is by Martin Kleppman at https://martin.kleppmann.com/2011/03/07/accounting-for-compu... — despite the name ("Accounting for Computer Scientists"), on reflection / trying it out, I find it less useful than the Beancount one.

(Both of these are actually linked in the second paragraph of the posted article, but they're independently worth mentioning / good.)