Toilets are a necessity in the 10 states I have visited in the U.S. They come in all different colors but there is always a standard design whether it's an outhouse or a luxury bathroom.
I have found out this isn't always the case in other countries. Problem such as an inconsistent water supply have resulted in some interesting, and at times disgusting, solutions. In addition, the design the U.S. has adopted isn't always what you will find while traveling. This can be quite confusing for a tourist, especially if you don't speak the language of the locals. If you are planning on traveling it might be helpful to research the bathroom situation before you go to avoid a potentially embarrassing situation!
Here are some interesting sites I found when I did that:
This is a great site with photos of what to expect when you travel to Japan. I've never been there but I thought there were some pretty innovative ideas, such as a toilet paper vending machine. I'm accustomed to seeing people asking for a few pesos in exchange for a couple squares of TP in Mexico, but Japan just took that to the next level!
U.S. Toilet Guide
I always thought the most sensible toilet was the one I used myself but this site showed me that ours may confuse foreigners. This page explains things like automatic flushing and proper terms to use when asking where the restroom is. Check out some of the other pages that discuss cultural differences. It makes you think about what an outsider has to do to understand some of the most basic activities in our country.
Lastly, here's a video of some girls traveling in Central America. Although the design is usually pretty similar to ours, sometimes these girls ran into some really oddly placed toilets. The audio is only helpful to hear where they are and Part Six goes on for more than two minutes. That bathroom is interesting because one of the girls was washing her hair when the water randomly went out.
CAUTIONARY NOTE: THIS IS KIND OF GROSS
So be advised that when you travel in a new country you might get confused by the toilet customs...be prepared to have an open mind and try not to offend anyone with your reaction if you get presented with a new type of toilet!