The "kōan" can be a special kind of metaphor with a hidden meaning, such as "the sound of one hand clapping".
ð ə WORD_BOUNDARY k oʊ n WORD_BOUNDARY k æ n WORD_BOUNDARY b iː WORD_BOUNDARY ʌ WORD_BOUNDARY s p ɛ ʃ ə l WORD_BOUNDARY k aɪ n d WORD_BOUNDARY ʌ v WORD_BOUNDARY m ɛ t ə f ɔ ɹ WORD_BOUNDARY w ɪ ð WORD_BOUNDARY ʌ WORD_BOUNDARY h ɪ d ə n WORD_BOUNDARY m iː n ɪ ŋ WORD_BOUNDARY s ʌ t̠ʃ WORD_BOUNDARY ʌ z WORD_BOUNDARY ð ə WORD_BOUNDARY s aʊ n d WORD_BOUNDARY ʌ v WORD_BOUNDARY w ʌ n WORD_BOUNDARY h æ n d WORD_BOUNDARY k l æ p ɪ ŋ WORD_BOUNDARY