Table show the (non-canonical) SMILES strings for the successful SMILES-based GA searches. In the case of troglitazone there were no successful searches, but 15 of the searches resulted in a maximum score of 0.79, which is the second highest score observed, so these string are counted as successful for the current discussion. Many of the SMILES strings show similar patterns. For celecoxib, all but two SMILES strings start with "NS(=O)(=O)C1=.." and end with "..C=C1". For troglitazone all but two SMILES strings start with "CC1=.." and end with "..C1O", or vice versa, and similarly for tiotixene. The most likely explanation is that each respective search starts from the same or similar SMILES strings in the initial population. Indeed inspection of the SMILES strings in the initial population reveal strings with similar patterns (Figure ). In the case of celecoxib there are 13 different molecules with the same phenyl-X-benzenesulfonamide architecture, which helps explain why celecoxib is rediscovered more frequently than tiotixene, where the SMILES pattern shown in Figure is the only example in the initial population. In the case of troglitazone, the search has to place a more complicated syntax (COC2=CC=C(CC3SC(=O)NC3=O)C=C2), compared to celecoxib and tiotixene, at the correct position in the string. While this can be done at the 5 position (Figure ), it is more difficult at the 2 position (which would result in troglitazone) due to the SMILES syntax of the chromane moiety that is most common in the initial population (Figure ). This observation could help explain why none of the SMILES-based troglitazone rediscovery searches are successful.