What means
It was a block tile for a character display. The main Japanese character set for Sharp MZ screens assigned this tile code F1. Sharp's MZ-80K personal computer launched in 1978. Semigraphic tiles used block patterns as chunky pixels, letting character cells make simple pictures on displays with limited direct pixel graphics.
Why does differ from ▘?
The gap is part of the separated pattern. Unicode pairs it with the solid upper-left quadrant ▘ as a separated counterpart. The Unicode 18.0 chart says reference glyphs do not prescribe font shape and fonts can vary; compare the gap and filled corner, not one exact outline.
Don't confuse it with
1Questions people ask
1Why does show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type
𜰡\1CC21Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.
