Polygonia comma form of comma is frequently confused with the dark form of the question mark ("P. interrogationis"), but the two can readily be distinguished by the shape of the comma mark on the underside. The pale form is easily confused with the satyr comma ("P. satyrus"), which usually occurs north and west of the eastern comma's range. They can be distinguished by the upperside color, which is orange brown in the comma and tawny yellowish brown in "P. satyrus"; by the underside pattern, which tends to be mottled in the comma but appears to be more longitudinally streaked in "P. satyrus";
Irony punctuation mark was used earlier by Marcellin Jobard in an article dated June 11, 1841, and commented in an 1842 report. Hervé Bazin, in his 1966 essay "Plumons l'Oiseau" (“Let's pluck the bird”), used the Greek letter ψ with a dot below for the same purpose . In the same work, the author proposed five other innovative punctuation marks: the “doubt point” , “conviction point” , “acclamation point” , “authority point” , and “love point” . In March 2007, the Dutch foundation CPNB "(Collectieve Propaganda van het Nederlandse Boek)" presented another design of an irony mark, the "ironieteken": (). Tom Driberg