Purple and Brown

A simple quiz

First i have to say that i hate maths, i never liked them and i was always forced to read them at school. I post the next ¨math¨ problem because in fact it is not a math problem and that is why i solved it in three minutes...max. Even a five year old child, that can count to ten, is able to find the solution.

Every line results from the previous line with a certain way. Can you find it? Is the last line the final or it continues? If so, which is the next line?