Density, temperature, and velocity profiles of a PION simulation with a single star model of Z = 0.004, υ_ini = 0 km s⁻¹, and log₁₀(M/M_⊙) = 1.5 in a uniform medium of n = 100 cm⁻³ at 5 Myr (top), at the end of the stellar lifetime (middle), and 5 Myr after the subsequent SN (bottom). Dashed lines indicate negative velocities. The circled numbers at the top indicate the five different regions found in the density profile due to pre-SN feedback.