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.
Quotation mark
The single quotation marks emerged around 1800 as a means of indicating a secondary level of quotation. One could expect that the logic of using the corresponding single mark would be applied everywhere, but it was not. In some languages using the angular quotation marks, the usage of single ones (‹…›) became obsolete, being replaced by double curved ones (“…”); the single ones still survive, for instance, in Switzerland. In Eastern Europe, the curved quotation marks („…“) are used as a secondary level when the angular marks («…») are used as a primary level.