These are some of the simple button icons i did for a custom application. The design requirement was for simplicity, and visual representation of the action to be performed.
the icons functions from the top left:
tune (like tune up your car, not music), contour skate (a curve fitting algorithm), duplicate curve.
The middle Row: measure, mark, re-center graph, clamp (another curve algorithm), smooth (more curve stuff), and show stats.
The bottom row: tangent, flatten, rotate, stretch