Sandi Metz rules for devs

Other than the first time I wrote some JS code that chained several callback functions that each required parameters and 
I ended up passing in 6 parameters to the initial function, I havent had to pass more then five parameters in ruby. Therefore 
I dont see the four method argument that challenging yet. So I then must say that the one instance variable per controller action
is probably the hardest to follow. I can think of numerous views that need access to different objects and classes. But the one
solution mentions (facade pattern) seemed like a easy solution to the one instance variable.