They tend to be dangerously brittle — meaning that changes to one area of the system will affect other seemingly unrelated areas — and therefore difficult and time consuming to refactor.

Verjuice: Madam, by this time Lady Brittle is the talk of half the town, and I doubt not in a week the men will toast her as a demirep.

At the same time, how to establish the failure criterion of brittle materials in biaxial stress state is one of people's goal.