Serial comma toast. Adding a serial comma removes this ambiguity. Writers who normally avoid the serial comma often use one in these circumstances, although sometimes re-ordering the elements of such a list can help as well. In some circumstances using the serial comma can create ambiguity. If the book dedication above is changed to the serial comma after "Ayn Rand" creates ambiguity about the writer's mother because it uses punctuation identical to that used for an appositive phrase, leaving it unclear whether this is a list of three entities (1, my mother; 2, Ayn Rand; and 3, God) or of only two
Punctuation to be more prominent) by using not differing height but rather a differing number of marks—aligned horizontally (or sometimes triangularly)—to signify a pause's value: one mark for a minor pause, two for a medium one, and three for a major. Most common were the "punctus", a comma-shaped mark, and a 7-shaped mark ("comma positura"), often used in combination. The same marks could be used in the margin to mark off quotations. In the late 8th century a different system emerged in France under the Carolingian dynasty. Originally indicating how the voice should be modulated when chanting the liturgy, the "positurae"