Outcomes of innovative designing are frequently described as enabling us in achieving more desirable futures. How can we design and innovate so as to enable future processes of design and innovation? To investigate this question, this thesis probes the conditions, possibilities and limitations of toolmaking for novelty and knowledge generation, or in other words, it examines designing for designing. The focus of this thesis is on the development of digital design tools that support the reconciliation of conflicting criteria centred on architectural geometry. Of particular interest are the roles of methodological approaches and of biological analogies as guides in toolmaking for design, as well as the possibility of generalising design tools beyond the contexts from which they originate. The presented investigation consists of an applied toolmaking study and a subsequent reflective analysis using second- order cybernetics as a theoretical framework. Observations made during the toolmaking study suggest that biological analogies can, in informal ways, inspire designing, including the designing of design tools. Design tools seem to enable the generation of novelty and knowledge beyond the contexts in and for which they are developed only if their users apply them in ways unanticipated by the toolmaker. Abstract The reflective analysis offers theoretical explanations for these observations based on aspects of second-order cybernetics. These aspects include the modelling of designing as a conversation, different relationships between observers (such as designers) and systems (such as designers engaged in their projects), the distinction between coded and uncoded knowledge, as well as processes underlying the production and the restriction of meaning. Initially aimed at the development of generally applicable, prescriptive digital tools for designing, the presented work results in a personal descriptive model of novelty and knowledge generation in science and design. This shift indicates a perspective change from a positivist to a relativist outlook on designing, which was accomplished over the course of the study. Investigating theory and practice of designing and of science, this study establishes an epistemological model of designing that accommodates and extends a number of theoretical concepts others have previously proposed. According to this model, both design and science generate and encode new knowledge through conversational processes, in which open-minded perception appears to be of greater innovative power than efforts to exercise control. The presented work substantiates and exemplifies radical constructivist theory of knowledge and novelty production, establishes correspondences between systems theory and design research theory and implies that mainstream scientific theories and practices are insufficient to account for and to guide innovation. Keywords (separated by commas) Digital design tools, geometry rationalisation, second-order cybernetics, knowledge generation