1. The Gemara explains why the prayers of the righteous are likened to a pitchfork.
2. There is a dispute in the Mishnah about the use of boards for Sechach.
3. Rav and Shmuel disagree about the nature of the dispute in the Mishnah (#2).
4. Rav Papa further explains the position of Shmuel (#3).
5. There is a dispute about boards of four Tefachim that were placed on their narrow sides as Sechach.
A BIT MORE
1. Just as a pitchfork is used to turn over produce and move it from one place to another, the prayers of the righteous move Hashem's mode of conduct from Din to Rachamim.
2. Rebbi Yehudah: They are permitted. Rebbi Meir: They are forbidden.
3. Rav: The Tana'im argue in a case where the boards are four Tefachim wide. Where they are less than four Tefachim wide, everyone agrees that they may be used as Sechach. Shmuel: They argue in a case where the boards are less than four Tefachim wide. Where they are four Tefachim wide, everyone agrees that they are invalid.
4. He explains that Shmuel says that everyone agrees that if the boards are less than three Tefachim wide, they are valid, and if they are four Tefachim wide, they are invalid. The argument between Rebbi Yehudah and Rebbi Meir is when they are between three and four Tefachim wide.
5. Rav Huna: They are invalid. Rabah bar Rav Huna and Rav Chisda: They are valid.