I came across this beautiful interpretation of the various ways Sula’s birthmark is perceived by different characters throughout the novel sketched by Rockset-hero. From the top to the bottom, the symbols are not exactly ordered chronologically, as I’m sure you have noticed. However, they are grouped in terms of their connotation. The “stemmed rose”, noted by members of Bottom society and even the narrator during Sula’s childhood, and the “tadpole”, which Shadrack sees as the marking of a friend when Sula enters his house following the Chicken Little incident, greatly contrast the much darker, sinister images below, the “snake”, “Hannah’s ashes”, and the “scary, black thing.” Despite the fact that each perception is a different image, each symbol appears to be linear and placed diagonally, which I see as their commonality as perceptions of the same image.