Here is a great video with explanations: https://www.youtube.com/watch?v=iphcyNWFD10 https://www.youtube.com/watch?v=iphcyNWFD10 Short answer - they use lots o

Here is a great video with explanations: https://www.youtube.com/watch?v=iphcyNWFD10 https://www.youtube.com/watch?v=iphcyNWFD10 Short answer - they use lots of techniques - its super hard.