I like the one with the lock and the spiral light one. The light writing is close. Master what you are trying to write first, then look straight at the camera while you do it and your face will be in focus but your arm will be a blur. It takes loooots of practice but there are some really neat things you can do with it.
It's my favourite one because the rainbow of light leads the eye to a cool bokeh and is rewarded. It has balance, strong lines, and decent atmosphere in my opinion. What do you think makes it a decent picture?