There was a really useful spreadsheet application for DEC's RSTS/E... named "calc" maybe? The innovative part of it was a cell formula included an output direct

There was a really useful spreadsheet application for DEC's RSTS/E... named "calc" maybe? The innovative part of it was a cell formula included an output directive. So the normal excel formula in cell b1 of "=sum(a1..a26)" has it's output written to b1. But with calc you could in cell b1 put "b2=sum(a1..a26)" and the result would be written to b2. This became super powerful when dealing with ranges. You could have 1 formula that that calculate the row-wise total for each row... and it would be in 1 cell, so for example "$1..$10=sum($1..$9)" (forgive me I can't recall the addressing specifics for relative/fixed/named ranges). It was pretty amazing at the time.