What are glyphs in Assassins Creed 2

In Assassin's Creed II the glyphs are 20 program files that Subject 16 hacked into the animus that need to be decoded in order to unlock them.In order to find them you need to look for them in certain locations that are marked with an eye icon.Also when you use Eagle Vision the glyph glows red while use Eagle Vision walk up to it to scan it.Now prepare yourself cause you have to solve some puzzles in order to unlock this file,Beware they may seem easy at first but they get harder each time you find one,luckly you can save it to unlock later.No you don't have to find them in any order so don't panic.Have fun finding them all since their scattered all across Italy.Enjoy these frustrating riddles and puzzles for when you find them all you will know THE TRUTH.