In this study, we aimed to present the features of pre-service teachers’ reasoning and sense making in the process of exploring growing patterns tasks. Participants were 79 pre-service primary teachers in Sweden. The analysis was grounded in the concept of critical aspects from variation theory and the concepts of assemblage, lines of flight, segmentarity, and rupture from a post-structuralist philosophical perspective. Results indicate that the concepts of assemblage, line of flight, rupture, and segmentarity can be useful tools for analyzing analysing reasoning and sense making in mathematics. The results also show that in mathematics, the line of flight can be seen in moments of creativity and innovation. Furthermore, the results show that rupture can be seen in the connection of concepts or ideas that challenge established mathematical structures and ways of thinking. Further, the results shows that segmentarity creates disciplinary boundaries and inhibits reasoning and sense making. Therefore, it is important to recognize and break down these boundaries to facilitate more creative and innovative reasoning and sense making in mathematics.