Code point
U+2290
Glyph appearance depends on your fonts.
U+2290
SmU+2290 SQUARE ORIGINAL OF is a Unicode 16.0.0 character in the Math Symbol category. It belongs to the Mathematical Operators block.
Choose the representation you need, then copy its value.
U+2290
8848
⊐
⊐
⊐
E2 8A 90
2290
00002290
%E2%8A%90
\u2290
\u2290
\u2290
\2290