Question mark
The rhetorical question mark or percontation point was invented by Henry Denham in the 1580s and was used at the end of a rhetorical question; however, its use died out in the 17th century. It was later revived in modern-day society by Matt DiRoberto. It was the reverse of an ordinary question mark, so that instead of the main opening pointing back into the sentence, it opened away from it. This character can be represented using the reversed question mark (⸮) found in Unicode as U+2E2E. The percontation point is analogous to the irony mark, but those are even more rarely seen.
Cadit quaestio
As a mark in copy editing, "cq" implies that the accuracy of a statement, fact, etc., has been verified. It is usually placed in a draft article by the writer, to the attention of the copy editor. The precise origin of the term is uncertain, but 'cq' was identified as the shorthand form of "correct" in the 1879 Phillips Code, a set of abbreviations used in the transmission of press reports via telegraph, first published in 1879. Alternate explanations of the origin include an abbreviation for "cadit quaestio", indicating that the issue is "no longer in question", and an abbreviation for "correct as quoted", which serves as a useful mnemonic. "Cq" is a mark for internal use only, intended for removal prior to publishing. It should be distinguished from the unrelated mark "sic", used in published pieces to indicate that a quote has been transcribed verbatim, without correcting perceived errors in the original source.