Space-time diagram for propagation of the PPI ejecta of a 50 M_⊙ He core. The color indicates the density, assuming radial expansion at constant velocity. The top panel indicates the cumulative amout of ejected at velocities larger than the escape velocity through pulses only (i.e., excluding the wind mass loss). The cyan curve shows the radius of the material instantaneously bound (cf. the red curve in Fig. 4).