From first word to plywood to post plywood to debut, Mason Dixon has been some time in the making. This is the bar on Essex Street owned and operated by Hell Square Booze Mayors Rob and Will Shamlian, who also own Dark Room, Fat Baby and Spitzer's Corner. In the end, this bar, complete with a country/Western theme and mechanical bull in the rear, will be the parcel in their holdings that make them Lower East Side heroes or villans. If Mason Dixon terrorizes, floods the streets with 20-ish drunks and their vomit, the scale tips in aggregate to show they're part of the problem Hell Square problem. If, on the other hand, it becomes a serviceable neighborhood bar, especially at off hours, it, along with Spitzer's makes them downtown heroes. Time will tell.