Snapshot of a statistically-steady nonlinear dynamo calculation (corresponding to case B4, with ζ₀ = 0.15 – see Table 2). Top: the vertical magnetic field distribution in the horizontal planes defined by z = 0.1 (left) and z = 0.5 (right), where the colour table has been saturated at B_z =  ± B_eq. Middle: as above, but here the contour levels have been saturated at ± 0.25B_eq to highlight some of the small-scale structure in the field distribution. Bottom: the corresponding temperature distributions for z = 0.1 (left) and z = 0.5 (right).