The sixty-story John Hancock Tower was built in Boston in the 1970s, and it was discovered to have an unexpected torsional instability. The interplay of the wind between the surrounding buildings and the tower itself was causing it to twist. Despite being designed in line with current building codes, torsional instability found a way to twist the building, and people on the top floors started feeling seasick. Once again, it was tuned mass dampers to the rescue! Lumps of lead weighing 330 tons were put in vats of oil on opposite ends of the fifty-eighth floor. Attached to the building by springs, the lead weights damp any twisting motion and keep the movement below noticeable levels. Humble Pi: A Comedy of Maths Errors