Shabbat 125: Intention to Move Something on Shabbat; What is Set Aside

The rabbis ask about things that are thrown aside before Shabbat.  Are we allowed to move those things later, on Shabbat?  Are they permitted to be moved only when they are or are not providing a purpose similar to their original function?  The rabbis use shards of an old oven as their example.

A new Mishna teaches that when a gourd that has a stone in it is used to draw water and the stone does not fall when it is poured, we may fill it on Shabbat.  If the stone falls, we may not use it to fill things.  When a vine ranch is tied to a pitcher, we may fill it with water on Shabbat because the branch has become part of the vessel.  Regarding a window shutter, Rabbi Eliezer teaches that when it is tied to the window and hanging down, we may shutter the window with it; it is not considered to be building.  If the shutter touches the ground, we may not use it to shutter the window.  The rabbis say that in both cases we are permitted to shutter the window.

The Gemara considers other cases regarding falling stones that may not be comparable to the first case described by our Mishna.  What kind of action is require to create vessels from stones?  Is an action required to be attached to something else to maintain its status as set aside?  Similarly, the Gemara discusses building with beams that may have been tied together on erev Shabbat so that they are not classified as set aside.  The rabbis speak of how much has to be planned in advance.

At the end of our daf the rabbis consider the case of a window shutter.  R. Yochanan had said that everyone agrees that we may not build a temporary tent on a Festival for the first time, and of course not on Shabbat.  Rabbi Eliezer said that we may not add to an existing structure on a Festival, and not on Shabbat.  The rabbis say that these things are alright - we may add to a temporary structure on Shabbat and on a Festival.