Don’t remind me of that. I wrote a spreadsheed spread over about ten files (for memory size reasons, and they had maxxed out the memory on the machine already). Every month, some poor being had to type in the results from the mainframe printouts into one sheet, then the data was referenced through a bunch of intermediate sheets that distributed the numbers in very creative ways, and then a final spreadsheet was called up to get all numbers referenced together to print them into the proper forms. Luckily there was some field referencing across files, or that would have become a real nightmare.