Simulated light curve of HD 37776 derived assuming the silicon and helium surface distribution by Khokhlova et al. (2000) and modulated by n = 3 and l = 3 multipole (solid line). This is compared with the TESS light curve phased with the nonlinear ephemeris from Mikulášek et al. (2020, dots) and with the light curve calculated purely from surface spots (dashed line). All light curves were shifted to derive a zero mean magnitude.