The Square with Upper Right To Lower Left Fill symbol (▨). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Geometric Shapes.
The quickest way is to copy ▨ from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
▨ is U+25A8 (decimal 9640).
Use ▨ in HTML to render ▨ on a web page.
On Windows you can type it with Alt+9640 (hold Alt and enter the number on the numeric keypad).
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