The Braille Pattern Dots-237 symbol (⡆). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Braille.
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+2846 (decimal 10310).
Use ⡆ in HTML to render ⡆ on a web page.
On Windows you can type it with Alt+10310 (hold Alt and enter the number on the numeric keypad).
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