It can be argued that the Google search algorithm is the most used form of mathematical engineering in history. With billions of searches performed daily, it’s easy to argue that it is used at the scale of many of the naturally-occurring algorithms that govern the world around us.

Last year, the search giant gave us the revelation that Google makes changes to the algorithm an average of once every 17.5 hours, but the vast majority of these changes go unnoticed by even the most scrutinizing observer. Some changes are major, and those are the ones that are detailed below in this infographic. Click to enlarge.