The Left Three Quarters Block symbol (▊). Copy and paste it, or use its Unicode, HTML, and CSS codes.
More from Block Elements.
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+258A (decimal 9610).
Use ▊ in HTML to render ▊ on a web page.
On Windows you can type it with Alt+9610 (hold Alt and enter the number on the numeric keypad).
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