Top panels: evolutionary tracks. Bottom panels: evolutionary diagrams. Left panels: skewness S. Right panels: kurtosis K. In the evolutionary tracks, the symbols along the tracks from left to right are for redshifts z = 30, 10, 5, 3, 1, and 0. In the evolutionary diagrams, the symbols from top to bottom correspond to smoothing lengths 2, 4, 8, and 16 h⁻¹ Mpc. The solid bold black curves show the skewness S(σ) and kurtosis K(σ) according to the log-normal distribution. The dashed curves show S = 3σ and K = 16σ².