The traditional way of taking a three-dimensional photograph, or hologram, involves splitting a laser beam in two, reflecting one half (known as the object beam) off the thing that is to be holographed, and then recombining it with the other half (known as the reference beam) and exposing a photographic film to the result.
The process of recombination produces an interference pattern that is recorded on the film, and when this pattern is viewed in suitable lighting, an image that looks three-dimensional becomes visible to the eye.
The Massachusetts Institute of Technology has some of its course materials available online -- for free.
With an Internet connection and a Web browser, you can access MIT's pilot project: OpenCourseWare which includes the syllabus, lecture notes, exams (with answers), and videotaped lectures of 32 MIT courses.
Sometimes I hear bits and pieces of song lyrics in my head. I find many of them to be particularly relevant, like Dave Matthews asking you "what would you say", or The Who exhorting you to "pick up your guitar and play".
Of course, it’s much easier said than done. There are so many other distractions, as well as necessary duties in life, that there is often little time left for anything unscheduled. As much as I love playing music, I often find that I need to have a goal in mind in order to make time to play.