Mistakes in computation, drawing and execution provide interesting information about the artist. At Palenque, Dos Pilas and elsewhere, blatant errors of mathematical computation or in the use of signs were not corrected. Either the Maya did not proofread the first drafts made by the masters, or errors were considered to be divine intervention and protected from correction. The frequency of such mistakes also suggests that the process of creating the master drawing was a ritual occasion of major importance that included fasting, bloodletting, and perhaps, heavy drinking of Maya beer, called balche. If so, the masters were probably not at their best when then drew the master painting.