In 2017, a neon maker in Auckland produced these Blue Knots for Billy Apple. The neon maker had been in the process of refurbishing Four Knots for R. D. Laing, a work made in 1966 from glass rods twisted into knots by a glassblower in Idaho Falls, where Apple had undertaken a Ford Foundation residential scholarship. These were then pumped with neon, helium, argon and mercury gasses to make a four-colour set (in red, pink, purple and blue). Linked by their title to the radical British psychiatrist R. D. Laing (1927–1989), they stand for the ‘knots’ Laing wrote about in his volume of poems of the same title. The psychiatrist’s deceptively simple wordplays tease out the divided nature of individual subjectivity, interpersonal relations and family dynamics. Apple read this book soon after it was published in 1970, adding Laing’s name to the title of his neon work in 1972. He also reutilised Laing’s taste for homonyms in an accompanying statement that both linked and distinguished each component, as in ‘Red knot is knot blue’, to create a three-dimensional version of Laing’s written conundrums.