An invention which at first sight appears obvious might in fact involve an inventive step. Once a new idea has been formulated, it can often be shown theoretically how it might be arrived at, starting from something known, by a series of apparently easy steps. The examiner must be wary of ex post facto analysis of this kind.

In the context of the problem-solution approach, it is permissible to combine the disclosure of one or more documents, parts of documents or other pieces of prior art (e.g. a public prior use or unwritten general technical knowledge) with the closest prior art.

This example illustrates the two-level technicality analysis set forth in section G‑VII, 5.4.

Claim 1:

The objective technical problem must be a technical problem which the skilled person in the particular technical field might have been asked to solve at the relevant date. It must not be formulated in such a way as to refer to matters of which the skilled person would only have become aware by knowledge of the solution claimed (G‑VII, 5.2). In other words, the objective technical problem must be so formulated as not to contain pointers to the technical solution.