For more than 100 years, machines have been replacing human physical labor, especially in jobs requiring great physical strength, or endurance, or extremely repetitive and well-defined motions. This has arguably accelerated in recent decades, and there is a current growing push for "lights out manufacturing," i.e. have no light-requiring humans in-the-loop.

It has proven harder to create robots that can substitute for the fine-grained dexterity and motor control of many physical tasks, especially those where the action must be in response to, or dictated by, visual or verbal information. Robots are, however, continually improving, and it is not hard to extrapolate to a time when most non-intellectual factory-type jobs can be done by autonomous systems that can be directly "slotted in" for a human worker. As a benchmark for the type of visual and manual processing required, we ask:

When will a robot exist that is able to completely assemble a generic Lego set?

For positive resolution, the system must be able to assemble on demand multiple possible production Lego sets of 50+ pieces. The box and bags may be open but the robot must turn the pages on the direction set. Credible video or report must exist of this being done. The robot can be a prototype rather than production model. Resolution can also be achieved by the existence of a robot that would, as judged by a robotics expert, very clearly be capable of assembling a Lego set.