LOL! I used same method than for 73: I studied the board a bit, to identify what block(s) I could use in a counter intuitive way. I saw one, tried making it work and won.
I was 2 off on my first try. I then studied the board a bit and had the feeling a certain block could be used in a counter intuitive way. I focused on trying to make that work and that was in deed the key! I won on 3rd try. Proud and happy me. :D