Each line is the surviving fraction of one spore population at one temperature — five retorts a few degrees apart, sharing the same clock. Death is log-linear: equal minutes remove equal fractions, so the count falls in straight decades on a log scale, and the D-value is the minutes per decade. Cooler lines fall slower, and the spacing is exact: every z degrees cooler multiplies D by ten. The 12-log cook that takes two and a half minutes at 121°C asks for an hour and forty minutes at 105°C. Every number on screen is computed from the model; nothing here is simulated.