Besides many theorems math does have design patterns; Tim Gowers in his essay "The two cultures in mathematics" argues that part of the reason mathematicians in

Besides many theorems math does have design patterns; Tim Gowers in his essay "The two cultures in mathematics" argues that part of the reason mathematicians in other fields sometimes think there's not much to combinatorics is that they ate used to having widely applicable insights implemented as theorems whereas combinatorics tends to have them as design patterns.