a) 畑 -> 累 -> 紛 -> 貧
畑 hatake - cultivated field
累 RUI - involvement, trouble, accumulation
紛 FUN, magi(reru), magi(rawashii) - be mistaken for, confusing
貧 HIN, BIN, mazu(shii) - poor
b) 弦 -> 畜 -> 累 -> 繕
弦 GEN, tsuru - string, bowstring
畜 CHIKU - animal raising, domestic animal
累 RUI - involvement, trouble, accumulation
繕 ZEN, tsukuro(u) - repair, mend