From a side view, the cervical (neck) region of the spine (C1 C7) is bent inward, the thoracic (upper back) region (T1 T12) bends outward, and the lumbar (lower back) region (L1 L5) bends inward.

In Proposition 18 he argues that there are no further convex regular polyhedra.

What was the greatest invention of the industrial revolution? Hans Rosling makes the case for the washing machine. With newly designed graphics from Gapminder, Rosling shows us the magic that pops up when economic growth and electricity turn a boring wash day into an intellectual day of reading.

Messier 86 (also known as M86 or NGC 4406) is an elliptical or lenticular galaxy in the constellation Virgo.

In any case, Theaetetus gave a mathematical description of all five and may have been responsible for the first known proof that no other convex regular polyhedra exist.

It's almost as if somebody came into your home and rewired your walls so that the next time you turned on the light switch, the toilet flushed three doors down, or your dishwasher went on, or your computer monitor turned off.

We've seen the creation of small computers in the '70s and early '80s, and who would have thought back then that every single person would not have just one computer but probably 20, in your home, and in not just your P.C. but in every device in your washing machine, your cell phone.