What █ means
It paints one character cell completely solid. Unicode inherited it from older character sets, including the IBM PC set (code page 437), China's GB 2312, Korea's KS X 1001 and Videotex mosaics. Those screens drew pictures from text cells. Its half and shaded relatives turn rows of cells into coarse pixels.
Don't confuse it with
1Combination ideas
2Questions people ask
1Why do my full blocks have gaps?
Usually the font. Proportional fonts, extra line spacing or wrapping break the grid; in a monospace terminal font adjacent blocks meet without seams.
How to type █
█\2588Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.

