The aesthetic aspects of an architectural design can, in most instances, be protected by copyright law; functional aspects are usually not protected by copyright, though they may potentially be protected by patents. In general, when an architect is commissioned to design a building, the commissioner gets an implied or formal single license to use the designs to build that building — re-use of the design by the commissioner, unless contemplated in the commissioning of the building by both the architect and the commissioner, is generally an infringement of the architect’s copyright. Copying of the design by someone other than the commissioner is also a copyright infringement. All of these issues may of course be regulated by the contract between the commissioner and the architect.