  Answering a question of Abbasi-Zadeh, Bansal, Guruganesh, Nikolov, Schwartz
and Singh (2018), we prove the existence of a slowed-down sticky Brownian
motion whose induced rounding for MAXCUT attains the Goemans--Williamson
approximation ratio. This is an especially simple particular case of the
general rounding framework of Krivine diffusions that we investigate elsewhere.
