The purpose of the paper is to present work patterns from two perspectives, the art expert´s and art forger´s, as the patterns can be retrieved from two Swedish criminal cases of fraud, the case "T" and the case "M". A minor purpose is to create a knowledge base extracted from literature regarding more general work patterns used by art experts when they work with attribution.   The method used can best be named descriptive. Forged artwork from nine artists are described and comments on the fake procedures are provided from buyers, forgers/sellers, middlemen (auction houses), police, prosecutors, experts, lawyers and the Stockholm District Court. The result in the paper can be summarized as follows: 1/ General work patterns with attribution: The track-paradigm is governing the expert´s work. As a start we have a time-setting, by identifying general style patterns in the artwork. Then there is a search for a possible geographical area where the work could have been created, and also a search for art schools and artist groups in that area. If a possible attribution of the work to an artist can be done, a search starts for that artist´s characteristics when it comes to motive, color selection, composition, figures, brush movements etc. Different types of physical measurements and tests can provide a complement to the qualitative analysis. The signature, if there is one, is examined and the provenance for the work is searched for. Information about the work in different archives can strengthen the results. 2/ “T” & “M” - the art expert´s patterns: All experts go directly to the alleged artist for a critical analysis of the specific work. First an overall evaluation is done, and that is often sufficient to reject the work. If necessary, details in the work are examined. If a signature is present, it is examined and compared with genuine ones. In some cases, technical studies are used to reach a definitive verdict. The police focus is to identify inaccuracies and fakes in the sales information, and to show efforts to hide information.    3/ “T” & “M” - the forger’s patterns: Art works from recent years are used as models for the creation of pastiches. Craftsmanship is toned down. Pitfalls are being circumvented by selection of genuine material ingredients and selection of secure image content related to the chosen artist. There is a thorough work with information creation to ensure the prospective buyer's desire for proof of authenticity. In parallel there is a work with cover up, and to secure information gaps.