It's a very simple drawing of a square. There is nothing remarkable about the square, it is a computer drawn square. The square is drawn with medium thick lines. There is nothing inside the square.
This is a Stop Filled icon. We've made it in iOS style
, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 13,300 icons, all in the same style and quality.