Shabbat 8

If one threw an object from a public domain to a pole in a private domain, even if the pole is very tall, one is obligated for passing from a public to a private domain. Does this match Rebbi's opinion regarding one who throw an item onto a protrusion? Abaye says they are not the same as the details of the case are different and the debate between Rebbi and the rabbis is on a different topic. Abaye brings a case where one throws a rounded basket from a private domain to a public domain. Does it depend on the size? Upon what else does it depend? Does it matter if it is thrown right size up or upside down (because of laws of levud)? How does one calculate the 4x4 width in a circular item? Ulla brings a case of a pole nine tefachim tall and says that since people use it to readjust their loads, it is considered public space. Would the same be true for a hole nine tefachim deep? There is a disagreement. Rava thinks it is not the same as using a hole to store things is not so convenient. Several questions are brought against Rava. What is the law regarding a threshold - does it depend on its size?