An automata, or a kinetic sculpture, is usually a decorative item which moves in some way. Popularized some hundreds of years ago with clockwork like mechanisms, they can more easily be made today using Lego Technic bricks.
Here is a kinetic sculpture which shows the somewhat rude two hand gesture, where the index finger of one hand is passed in and out of a loop formed by the thumb and index finger of the other, suggesting coitus.
At the same time, the whole contraption also rotates, as you can see in this video:
The hand itself is made mostly out of fairly common bricks and plates:
The most used special plate is the 1x2 plate with handle (60478). Each finger uses three of them:
I got these parts mostly from the Mixels Busto set, which has six of them each. The hand can be posed in a fairly realistic way:
Not so visible in the video, but the base of the contraption is made with rubber wheels as "feet", to make it more stable. The motor powers both the rotation and the contraction of the yellow arms. The motor output is geared down 1:8 using a worm gear and a z8, and the 8:56 as the z8 (8 teeth cog) meshes with the outside of the big turntable: