The spell arcane lock can be cast on "a closed door, window, gate, chest, or other entryway." What are limits of this entryway? That is, must this entryway have a flap, lid, or other type of barrier in order for the spell to function?
And if the entryway can be open such as an archway, what constitutes an entryway? Does it have to have a certain amount of sides? Or could it be simply the gap between two poles?