The subtractive sculptural method involves material not being used (i. e. carving out of a block of wood or stone).

saw or carve or remove

Explanation:

Subtractive sculpture is one of the methods used to carve wooden or stone sculptures. In this method, the unwanted or the extra part of the wood or the stone is carved out so that a finished sculpture is formed out of it. The artists starts to carve bigger product so that after eliminating some of the products, the complete product is given the shape. This method is the oldest method that the artists have been using to form sculpture.

the answer of "what has three legs but never walks" is a yard stick. this answer can be found at