The idea for an invention may be developed on paper or on a computer, by writing or drawing, by trial and error, by making models, by experimenting, by testing and/or by making the invention in its whole form. Brainstorming also can spark new ideas for an invention. Collaborative creative processes are frequently used by engineers, designers, architects and scientists. Co-inventors are frequently named on patents.
In addition, many inventors keep records of their working process - notebooks, photos, etc., including Leonardo da Vinci, Galileo Galilei, Evangelista Torricelli, Thomas Jefferson and Albert Einstein.
In the process of developing an invention, the initial idea may change. The invention may become simpler, more practical, it may expand, or it may even morph into something totally different. Working on one invention can lead to others too.
History shows that turning the concept of an invention into a working device is not always swift or direct. Inventions may also become more useful after time passes and other changes occur. For example, the parachute became more useful once powered flight was a reality.