\sli{
Errors, bugs
{\em -- \zline{recovery}}
[A] -- algorithm awry
-[B] -- blunder
-[C] -- structure debacle
-[F] -- forgotten function
-[L] -- language liability
-[M] -- mismatch between modules
-[R] -- reinforcement of robustness
-[S] -- surprises
-[T] -- a trivial typo
}