Mostly the conceptual evolution was:

Knitting patterns have a lot of numbers with mathematical relations between them. You could keep track of them by hand, but spreadsheets are already an improvement. Especially when you want to make edits to earlier parts of the pattern. Well, spreadsheets aren't too bad to write, but they are basically write-only software, impossible to audit. She'd already learned programming in Haskell before, so going from there to using Haskell for making the numbers work out was a small step, conceptually.