Klaassen, BernhardBernhardKlaassen2022-05-062022-05-062022-02https://publica.fraunhofer.de/handle/publica/41631410.1016/j.ejc.2021.103454The so-called “einstein problem” (a pun playing with the famous scientist’s name and the German term “ein Stein” for “one stone”) asks for a simply connected prototile only allowing nonperiodic tilings without need of any matching rule. So far, researchers come only close to this demand by defining decorated prototiles forcing nonperiodicity of any generated tiling using matching rules. In this paper a class of spiral tilings (and one non-spiral example) is linked to a weaker form of the einstein problem where one or several seed tiles are used. Furthermore, the classical types of matching rules are listed and some new types are discussed.en003510005006518journal article