The area chart has a flat bottom with two sets of line going up and down. The top set of lines has dots interspersed throughout to indicate that it measures something different than the bottom set of lines.
This Area Chart 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 5,700 icons, all in the same style and quality.