9.21.10 Several obvious steps

If the technical problem that the skilled person has set themselves to solve brings them to the solution step by step, with each individual step being obvious to them in terms of what they have achieved so far and what remains to be done, the solution is obvious to the skilled person on the basis of the prior art, even if two or more such steps are required, and it does not involve an inventive step (T 623/97, T 911/98, T 558/00, T 1514/05).