Predicted average intensity in the direction parallel to c* for a crystal (space group P1, unit-cell parameters a = b = c = 50 Å, α = β = γ = 90°) containing two copies [separated by a fractional translation of (0.47, 0.47, 0.47), i.e. approximately body-centred] of a spherical molecule (r = 20 Å) comprised of 200 single-electron point scatterers. The solid lines shows the case in which the two copies are identical in conformation but differ by a 5° rotation around the x axis (black line) or around the z axis (grey line). The dashed line shows the case in which the two copies are in the same orientation but have r.m.s. coordinate differences of 1.5 Å.