[KenWittlief]

A company that made robot floor cleaners installed a new machine in a 20 story office building. The machine worked correctly on the first 5 floors, cleaning the floors in all the hallways, so they turned it over to the janitor crew. All the crew had to do was take care of the water and soap tanks, take the robot to the next floor on the elevator, and hit the run button.

On the 14th floor the robot cleaned half the floors, then made a sharp right turn and went through a thin plasterboard wall into someones office.

The robot cleaner was taken back to the factory, thoroughly diagnosed, some boards were replaced, and it was sent back. The wall on the 14th floor was repaired.

The factory crew followed the robot carefully as it cleaned the first 10 floors, declared it was fixed, and turned it over to the janitor crew again.

On the 14th floor it turned sharply again and went right through the freshly painted repaired wall.

On site testing revealed that a telephone microwave repeater antenna on the roof of a nearby building was sending a side-lobe of microwave energy through the building, on the 14th floor, in that one spot. It was strong enough to scramble the sensors on the robot and make it jump out of its SW loop.

Whole new meaning to the slogan "reach out and touch someone"

or something! :^)