Model A, the two-stage warmup model, for H₂CO (top) and CH₃CCH (bottom). The 10 K cold cloud stage (left) is followed by a warmup stage where the LTE components are separated based on the temperatures and densities observed. The time axis represents the age of each component independently. The components of each model are in dotted, dashed, or solid lines; red or green lines are the model abundances in the gas phase, yellow the model abundances in the grain phase, and black the observed abundances calculated from the averages in Table 2.