Answer: current Daf Yomi Seder.
More(!) seriously, I have to answer humbly “I do not know” to the OP’s question – despite years of diligent study with a personal tutor. Even after the tutor and I introduced. B’H, several more exemplars into the world and I was zoche to observe them closely, first in vivo and then in vitro – I still cannot comprehend them. But the Seder is not over, so I am still holding hope.