I suggest that you maybe looking at/doing it wrong. See my other comments in this thread for some notes that may inspire you to give it another try but with a d

I suggest that you maybe looking at/doing it wrong. See my other comments in this thread for some notes that may inspire you to give it another try but with a different mindset. The reason i say this is that i used to be in the same boat i.e. i can do everything within my head and don't need any external crutches. But once complexity really swamped me (it has become the norm now) nothing but pen and paper has helped me to effectively tame it. See also Dijkstra's paper, The Humble Programmer.