LEGO Technic Difference Engine | Make:

Andrew Carol's LEGO contraption "Before the day of computers and pocket calculators all mathematics was done by hand. Great effort was expended to compose trigonometric and logarithmic tables for navigation, scientific investigation, and engineering purposes. In the mid-19th century, people began to design machines to automate this error prone process. Many machines of various designs were eventually built. The most famous of these machines is the Babbage Difference Engine. Because of engineering issues as well as political and personal conflict the Babbage Difference engines construction had to wait until 1991 when the Science Museum in London decided to build the Babbage Difference Engine No.2 for an exhibit on the history of computers. Babbage's design could evaluate 7th order polynomials to 31 digits of accuracy. I set out to build a working Difference Engine using LEGO parts which could compute 2nd or 3rd order polynomials to 3 or 4 digits." Link.