The Bebras challenge on informatics originated 15 years ago, by now involves over 60 countries, and consists of short problem-solving tasks based on informatics (computing, computer science) and computational thinking. This paper deals with learning taxonomies and models that do not focus merely on partitioning computer science into its subareas, but rather on competencies that the learners can reach by working with information, data, algorithms, and automation processes. The contribution of this paper is a new concept for classifying tasks that also offers new ideas for generating tasks and which is used for creating spiral curricula for teaching informatics. One advantage of our approach is that the classes are not mutually exclusive, which reflects the fact that a task can support the development of different competencies in several areas. This allows to specify the benefits of working on a given task much more precisely and can thus help teachers to design and choose adequate tasks. Another advantage of this approach is the inclusion of important competencies that are not subject specific but are nevertheless important for the holistic development of school education. In addition, the proposed model can be used to develop informatics tasks (assignments), that are not only described by the topics to be covered, but also in competencies for the learners to reach.