About QUADRANT UPPER LEFT AND UPPER RIGHT AND LOWER LEFT
Quadrant Upper Left And Upper Right And Lower Left (U+259B) is a Unicode other symbol from the Block Elements block. It resides on Plane 0 (BMP, Basic Multilingual Plane), has bidirectional class ON (other neutrals), is not mirrored, and has combining class 0 (Not Reordered). In HTML it can be written as ▛ or ▛.