Wykres pierscieniowy and other 65,000 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 icon is shaped like a circle with a smaller circle at the center. The main circle is divided into three section. The larger section at the left is plain, the smallest section at the top right is striped, and the medium size portion towards the right is dotted.