This is a black small square, it also has three magnification forms：
◾️ black small medium square,
◼️ black medium square and
⬛️ black large 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 emojis：
⚫️ black circles,
⚪️ white circles.