She further discussed with fans that she's synesthetic, a neurological condition that allows people to experience senses different ways. Lorde's being that she can see sounds as colors, although she is one of the lucky ones whose synesthesia is not debilitating.
"When we first started tennis court we just had that pad playing the chords, and it was the worst textured tan colour, like really dated, and it made me feel sick, and then we figured out that pre chorus and i started the lyric and the song changed to all these incredible greens overnight!!!" she detailed.