This is a corner puzzle piece -one that would go in the southeast corner of a puzzle. The shape is roughly square. There is a protruding nub on the top. On the left is a space where the protrusion from another piece would fit.
This Puzzle 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.