On a phonemic level, phenomena of synesthesia have often been described and studied. Practically all children and a good many adults—though for the most part adults will deny it—spontaneously associate sounds, whether phonemes or the timbre of musical instruments, with colors and forms.

We tend to think of the seafloor a few kilometres down as a flat plain. In fact, about two-thirds of this “abyssal” seabed is made up of gentle rolling hills a few hundred metres high, says Jennifer Durden at the University of Southampton, UK.

Ow, he is just a wood harum-scarum creature, that wad never take to his studies;—daft, sir, clean daft. / […] / [W]owff—a wee bit by the East-Nook or sae; it's a common case—the ae half of the warld thinks t'other daft. I have met with folks in my day, that thought I was daft mysell;[…] / I cannot make out a word of his cursed brogue, said the Cumbrian justice; can you, neighbour—eh? What can he mean by deft? / He means mad, said the party appealed to, thrown off his guard by impatience of this protracted discussion.

And we mus[t]n't forget Three of Hearts, a feature-length documentary about the nine- year trinogamous relationship among bisexual men Sam Cagnina and Steven Margolis and heterosexual woman Samantha Singh.