I too have a BE but have not yet got those pattern skills!!!
Practice makes perfect ! With this machine, its fairly difficult to get the right milk froth, and even more so to do it consistently. It can be too runny as this prevents any pattern and you basically just have milk over the espresso, and you cant have it too thick as this gives you a nice blob of froth right on top (This can be cool for drawing designs though if you have the latte art tool. I sometimes do this on purpose to make a different non poured design).
But if you get it just right, the key is the mix high and rather slow in a circular pattern, then without changing the speed of the pour, come down lower and in the middle of the cup. When you come down lower the design starts to form and then its just about practicing the wiggle to ensure the zig zag pattern appears.
All easier said than done though
i still cant get it consistent from day to day.