Beitzah, Chapter 4, Mishnah 6. The Mishnah continues its discussion of wood on Yom Tov, this time dealing with very small slivers of wood: what their status is, and for which purposes one may pick them up.
The view of Rabbi Eliezer:
"Notel adam keisam mishelefanav lachtzos bo shinav" - a person may take a splinter, a small sliver of wood lying before him, and pick his teeth with it, the way one uses a toothpick. The wording "mishelefanav" (from what is before him) indicates that we are speaking of something actually lying before him, in his house.
"Umegabev min hechatzer umadlik, shekol mah shebechatzer muchan hu" - for the purpose of kindling a fire, one is permitted to gather not only from what is before him, but from anywhere in the courtyard, since everything in the courtyard is considered prepared and available for kindling on Yom Tov.
It is worth noting that some understand that even regarding the splinter the term "mishelefanav" is not meant precisely, and one may take from anywhere in the courtyard as well. We have used the wording "mishelefanav" here because the Sages disagree on this point too, and therefore it was presented as part of Rabbi Eliezer's novel ruling.
The view of the Sages:
The Sages say "megabev mishelefanav umadlik" - one gathers from what is before him and kindles - and they disagree on two points:
The scope of the gathering: one may gather only from what is actually before him, and not from the entire courtyard.
The permitted use: the wood may be used only for kindling. The wood is designated for making a fire, not for picking one's teeth, since that is not a use for which the wood was prepared in advance.
And even for kindling, one may take only from items prepared for him in his house, arranged and set aside for that purpose. But small pieces of wood that happen to be lying in the courtyard, which he gathers from there, were never on his mind and were never intended for kindling, and therefore they are not included in what is considered prepared.
In summary: Rabbi Eliezer and the Sages disagree about the status of wood slivers on Yom Tov. According to Rabbi Eliezer, one may take a splinter from what is before him to pick his teeth, and may gather from anywhere in the courtyard for kindling, since everything in the courtyard is prepared. According to the Sages, one may gather only from what is before him, and may use the wood only for kindling, since something that happens to be lying in the courtyard was never prepared and was never given any thought.