Dr. Asko Parpola takes an in-depth look at the recent claims of other researchers like Bryan K. Wells and Andreas Fuls that the Indus script has upward of 700 different signs. Despite the "wealth of new information" contained in the sign sets made by these researchers, Dr. Parpola argues quite coherently that the researchers are mistaking variants of single signs, and suffers from the "false conflation of two graphemes into one." He offers his own criteria of how to spot true variants (allographs) of a grapheme, and in general notes that we should expect signs to undergo changes if not transformations during a 700 year period. This is a technical discussion, but very important in terms of framing recent work and helps to anchor Parpola and Mahadevan's more modest sign lists (around 400) as a better foundation for research and decipherment. Dr. Parpola is the recognized authority on the Indus script, with important books and research covering many decades.