1358. Why do these characters seem to reverberate? 心 暖 勧 筒 慎

Answer:

They each have a reading that repeats a sound.

心  SHIN, kokoro - heart

暖  DAN, atata(kai), atata(meru) - warm

勧  KAN, susu(meru) - recommend, offer, advise

筒  TOU, tsutsu - pipe, tube

慎  SHIN, tsutsushi(mu) - be discreet, careful, restrain self