Many of my longtime readers probably know by now that major arteries such as Gravois or North Florissant were widened due to a bond issue passed by voters back in the first decades of the Twentieth Century. Amazingly, Gravois Avenue was a two-lane street before this. But what you might not realize is that between Twelfth (Tucker) and Jefferson Avenue, the street engineers also straightened Gravois, and there are remnants in a couple of buildings, such as the one above, which is still oriented along the old bend in the artery.
Likewise, this strange isolated lot is trapped inside a triangular block, only accessible through this gate along Gravois, due to the street widening and reorientation. It is located where you see the “1387” above in the old Sanborn Map, which also preserves the old crooked street grid. Remember, property owners who had twenty to thirty feet of their buildings taken by eminent domain had their front façades rebuilt for free by the City, thus making it hard to tell the streets were not originally so wide.
See some of the streets tucked away to the south of the bend in this post from July of 2020 about Salena and Cushing streets.