For a while I gave myself up entirely to the intense enjoyment of picturing machines and devising new forms. It was a mental state of happiness about as complete as I have ever known in life. … When natural inclination develops into a passionate desire, one advances towards his goal in seven−league boots. In less than two months I evolved virtually all the types of motors and modifications of the system which are now identified with my name, and which are used under many other names all over the world. It was, perhaps, providential that the necessities of existence commanded a temporary halt to this consuming activity of the mind.
My Inventions (1919), Chapter 4 : Tesla Coil and Transformer