Ah, someone did not read the Turbo Pascal manual! :)
Thankfully there is Bitsavers.
"Circular Unit References" chapter on the Turbo Pascal 5.0 programmer's user guide.
https://archive.org/details/bitsavers_borlandturVersion5.0Us...
Ha, I must've forgot about it completely! Thank you! And yes, I've never read the manual (unlike the tons of "C" books that followed). Pascal was simply thought orally, and on your own (back then), and that was the case for quite a lot of apps....
"Uses BGI;" and I'm done :)