I was writing things for fun yesterday and i made this peace of code. It it does one simple and dangerous task (kidding, thats not so dangerous, you can run it on you computer and see what happens).

So, the challenge is: can you describe what this code is really doing? Can you shine a light on it describing as many steps as possible?

<?php $§=(rawurldecode('%24__%3D%5B%22%3D%22%2C%22s%22%2C%22T%22%2C%22K%22%2C%22f%22%2C%22R%22%2C%22C%22%2C%22K%22%2C%22r%22%2C%225%22%2C%22W%22%2C%22a%22%2C%22s%22%2C%225%22%2C%22W%22%2C%22d%22%5D%3B'));assert($§);$_=__FILE__;assert(base64_decode(strrev(implode($__))));

you can use ctrl+c + v, or use the string version below:

<?php $§=(rawurldecode('%24__%3D%5B%22%3D%22%2C%22s%22%2C%22T%22%2C%22K%22%2C%22f%22%2C%22R%22%2C%22C%22%2C%22K%22%2C%22r%22%2C%225%22%2C%22W%22%2C%22a%22%2C%22s%22%2C%225%22%2C%22W%22%2C%22d%22%5D%3B'));assert($§);$_=__FILE__;assert(base64_decode(strrev(implode($__))));

Is not big deal, but its not that easy too. Experienced developers maybe can find the answer fast, but i believe that can be specially fun to beginners.