A pulley having different faces of different diameters giving various speeds according to the face the belt passes over.

Third-person singular simple present indicative form of gag

An instrument consisting of a tube containing mirrors and loose, colourful beads or other objects; when the tube is looked into and rotated, a succession of symmetrical designs can be seen.

(idiomatic) With the intention or goal of (followed by a noun or the infinitive).