cisnes negros:
elefantes negros:
medusas negras:
ver: https://translate.google.es/translate?hl=es&tab=rT&sl=en&tl=es&u=https%3A%2F%2Fpostnormaltim.es%2Fessentials%2Fmenagerie-postnormal-potentialities
ver: https://lamenteesmaravillosa.com/el-cisne-la-medusa-y-el-elefante-negros-tres-metaforas-de-lo-inesperado/