*** Weave timeout | 30.59s --> Input: \f -> f "" "" == "" && (f "a" "" == "a") && (f "" "1" == "1") && (f "a" "1" == "a1") && (f "ab" "1" == "a1b") && (f "a" "12" == "a12") && (f "" "12" == "12") && (f "ab" "" == "ab") && (f "ab" "12" == "a1b2")