A roundabout way of turning on a light. See the explanation b4 reading(kosherswitch.com)

   Sabbath law prohibits Jews from performing actions that cause a direct reaction;
   that would qualify as forbidden work. But indirect reactions are, well, kosher. In
   Hebrew, this concept is called the gramma. There are two types of grammas,
   Ottensoser tells me. Say you hit a light switch, but it doesn't come on
   immediately - that's a time delay, a time gramma. There's also a gramma of
   mechanical indirectness, like a Rube Goldberg contraption in which a mouse turns a
   wheel that swings a hammer that turns a key that launches a rocket. You can't
   claim the mouse actually launches the rocket.