This is the longest of the three periods. It is defiantly still going on today. People that have analyzed our rate of growth say that this period is not going to end any time soon. Many things similar to the inventions during the comfort period kept being invented, even more quickly that before, but they got overshadowed. You can see right at the end of the previous period things like the modem and pacemaker were invented. These signaled the start of the computer age. Most of the inventions during this time period were things to do with electronics. Once smaller parts started being made, these inventions became much more plausible. The calculator and word processor are examples of useful things, but many things like cassettes, CD's, videodiscs, and video games were created and marketed for our enjoyment. But it's more than that. The reason that this period is so large is that everything is intertwined. It would be extremely hard to distinguish separate periods for medical inventions, like the pacemaker and Valium, and personal use inventions on the same timeline, since they happen at the exact same time. Things used to be invented as they were needed, so things were similar, but now not many things are truly needed, so we just invent whatever we want.