Idea of Ascending Sorting Icon
There is 5 horizontal lines going downwards and as they go down they get progressively longer and longer, to the right of these lines is a single arrow pointing downward, starting at the base of the first horizontal line and ending at the final line.
This Ascending Sorting 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.