Idea of Inactive State Icon
This can be described as a series of small line segments placed at equal distance in such a way that they forms a circle.
This Inactive State icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,200 icons, all in the same style and quality.