The pulley.

I think that the pulley is the best invention of the history, the pulley and the wheel are esential to do every building, and without buildings we're not humans.

The first mention of the pulley was in 100 a.C. , when Plutarch (46/50 a.C.- 120 a.C.) ( in Parallel lives wrote that one day Archimedes (287 b.C.-212 b.C.) said to the king Hieron of Syracuse that he can move the Earth without effort, and he moves a ship of the king's army with pulleys, and obviously, without effort.

The pulley is composed of a wheel on a shaft with a groove, and a rope runs over the wheel and inside the groove. Pulleys are used to change the direction of a force, and also to reduce the effort done to move a weight, when in a pulley sistem you put a pulley, the effort is the result of divide the weigth by the number of pulleys, for example, if you put 1 pulley, you will do the same effort as the weight, but in other direction, but if you put 2 pulley, the effort will be 1/2 of the weight, and you can put any number of pulleys. With arround 1000 pulleys, you can carry a car with one hand!

But I think that the pulley wasn't invented by Archimedes, the Egypcians maybe used it 3000 years before to do the pyramids, carry 5t stone blocks isn't very easy.

For this and other things I think that the pulley is the vest invention of the humans.

My name.

My name, David, comes from the Hebrew, and means: who is loved by God.
My father choose it, I don't know why he did it but I like the name. The meaning is not the best for me, I only belive on things that I can see.

Led Zeppellin: Stairway to heaven.

Led Zeppellin were an English band formed in 1968 by Jimmie Page, Robert Plant, John Paul Jones and John Paul Bonham. In 1971 they released their fourth album, Led Zeppellin IV, and the song Stairway to heaven becomes very famous early, it was written by Jimmy Page and Robert Plant. But in 1980 some Christian evangelist in the US alleged that a hidden message was hidden in Stairway to heaven, they said it was a Satanic message.


In 1982 the Consumer Protection and Toxic Materials Committee of the California State Assembly heard the song backwards, and during the hearing a self-described neuroscientist said that the human brain can decipher hidden messages. But later a group of scientist discovered that the messages were false, the group also said that it's a waste of time try to find hidden messages, if the hidden messages work, all the songs will include ''buy this album''.

And here the song:
http://www.youtube.com/watch?v=w9TGj2jrJk8

Groundskeeper Willie

One of my favourite character from the Simpsons is Willie, the groundskeeper of Springfield Elementary School. Willie is voiced by Dan Castellaneta. Willie is a Scotish immigrant, almost feral in nature and immensely proud of his homeland. He is easily identifiable by his flaming red hair and beard, as well as his stereotypical Scottish accent.

Groundskeeper Willie's first appearance was in the season two episode "Principal Charming". Originally, the character was written just as an angry janitor; his Scottish accent was added during a recording session.