This paper presents a study based on didactic engineering and the theory of didactical situations on the complexification of the Leonardo sequence, addressing its numbers in a two-dimensional way, with the insertion of the imaginary unit "i". This study is an excerpt from a masters' thesis research done in the postgraduate programme in science and mathematics teaching of the Federal Institute of Ceará. It was conducted via Google Meet in an initial teacher education class in History of Mathematics. We will present a problem situation based on the research and the teaching methodologies assumed in it to evaluate the students' investigative and intuitive side faced with the situation presented. We assessed the results according to the methodologies used and carried out an internal validation. Thus, we concluded that the students could build their knowledge themselves, becoming protagonists of this construction and obtaining an evolutionary understanding of the Leonardo sequence.