Top row: logarithmic wind density structure. From left to right: OSG1, OSG2, BSG1, BSG2. Bottom row: wind velocity structure of the corresponding models. The rarefied medium in the density plot is characterized by high velocities, while the dense clumps move at much lower velocities. All models extend to 300 ks, but the B supergiant models actually run for a much longer time (see text). Also illustrated is the difference in dynamical timescale that governs the onset of structure formation.