Wiek and other 74,400 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
The appears the be a calendar or notepad. It is a square with two triangles on it. One triangle points up and there is another triangle directly under it that points down. Both triangles are the same size as each other. There are two pegs on the top of the image.