This is a black large square, and it also has three reduced forms of
▪️ black small square,
◾️ black medium-small square and
◼️ black medium square . On the Internet, people use it as a black color card or as a decoration symbol for text content. When it appears with
⬜️ white squares, we think of mosaics. Related to it are
⚫️ black circle,
⚪️ white circle, mosaic.