instruction:
This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
question:
Passage: The other Ancient Greek dialects, Ionic, Doric, Aeolic, and Arcadocypriot, likely had the same three-way distinction at one point, but Doric seems to have had a fricative in place of /tʰ/ in the Classical period, and the Ionic and Aeolic dialects sometimes lost aspiration (psilosis).
answer:
What ancient dialects had the same two-way distinction at one point?


question:
Passage: The innovative production techniques devised by post-punk producers such as Martin Hannett and Dennis Bovell during this period would become an important element of the emerging music, with studio experimentation taking a central role. A variety of groups that predated punk, such as Cabaret Voltaire and Throbbing Gristle, experimented with crude production techniques and electronic instruments in tandem with performance art methods and influence from transgressive literature, ultimately helping to pioneer industrial music. Throbbing Gristle's independent label Industrial Records would become a hub for this scene and provide it with its namesake.
answer:
Who avoided post-punk production?


question:
Passage: Mass production of glass window panes in the early twentieth century caused a similar effect. In glass factories, molten glass was poured onto a large cooling table and allowed to spread. The resulting glass is thicker at the location of the pour, located at the center of the large sheet. These sheets were cut into smaller window panes with nonuniform thickness, typically with the location of the pour centered in one of the panes (known as "bull's-eyes") for decorative effect. Modern glass intended for windows is produced as float glass and is very uniform in thickness.
answer:

What were the areas at the center of window panes called?