The icon resemble a three dimensional square shape with curved corners and a hollow center that is also the same shape. The square has two horizontal lines running through the middle top and middle bottom of it.
This OpenStack 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 5,500 icons, all in the same style and quality.