Who is not familiar with it? Whoever we are, both as parents, teachers or students, must be familiar with all three.

When we opened the bag and daughters of our beloved son, secured in it we will find things very simple. It was indeed very simple with simple functions as well. We recognize all three as a tool to leave a trail., Or replace the paper is wrong, then overwrite it with writing that is considered correct.

But you are announcing, that with it also traces opinions, thoughts or answers that we do as if lost and overshadowed. Scribbles disappear and the way our science can not be read back. Though graffiti it is worth it to get the best intentions.

We will never know is right without knowing wrong. We would not be understood without recognizing that it is positive negative.

Therefore let the mistakes and errors that still exist, simply mark (corrected) with scribbles do not need to be removed or covered. As it turns out the errors that many teaching us about the truth.