Spiral
The toolpath follows contours that are offset inward from the material boundary.
Zig Zag
The tool motion consists of:
Linear moves across the material,
Followed by offset moves parallel to the material boundary, to the beginning of a return move,
A return move that is parallel to, and in the opposite direction of, the previous linear move.
The linear moves are parallel to a vector you are prompted to identify.
Zig
The tool motion is similar to Zig Zag except the tool re-positions after each cut so that all cutting motion is always in the same direction.