A bit short on details. What exactly was it about this spreadsheet that made it hard to recreate in a programming language? Personally I find this hard to bel

A bit short on details. What exactly was it about this spreadsheet that made it hard to recreate in a programming language? Personally I find this hard to believe unless one of the key deliverables is "pretty much every parameter to this calculation must be tweakable by the user with the results being visualised instantly".