This icon is a part of a collection of Siatka Aktywności 2 flat icons produced by Icons8. Icons follow the guidelines of iOS, Windows, and Android and are designed by a single designer, guaranteeing the consistent quality. Both PNG and vector are available.
It's an image of 16 rectangles, slightly longer than they are wide. The rectangles are placed in 4 rows of 4 columns, in such a way that the shape they make up when considered all together is also a rectangle.