Shabbat 29 - A folded garment
If one took a small piece of clothing, the size of three by three finger-breadths, and folded it into a wick, but did not singe it as yet, then Rabbi Eliezer says that it is still a garment, and therefore can become ritually impure. According to Rabbi Eliezer, merely folding a garment into a wick does not change the fact that it is a garment; additional singeing would make it into a wick, and it would not accept ritual impurity any longer. Rabbi Akiva, however, says that folding a garment does make it into a complete wick, and it is not susceptible to impurity.
They further argue if one can actually light this wick for Shabbat, Rabbi Eliezer stating that one may not, and Rabbi Akiva - that one may. Why would one not be allowed to light it? We must say that they argue only in the case when Friday is a Yom Tov. Still, why we would not use the wick? - While it is still three by three finger-breadths, it is a "complete garment," or at least usable for a patch. Once it starts burning, it becomes less than the minimal size, and thus it is something new that was created on a Yom Tov. According to Rabbi Eliezer, there is a prohibition to use broken pieces of utensils, because they are new entities, not designated initially for use. Such entities are called "set aside," or "muktzeh" and that is why the wick cannot be used. The Talmud give two more possible explanations of their disagreement.
Art: Trophîme Bigot - Girl pouring oil into a lamp