This Żywioł wody 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 4,300 icons, all in the same style and quality.
This particular icon features lines that are curved, placed on top of each other, and run parallel to each other. They are positioned horizontally. The top lines are much more curved than the bottom ones.