Federalism is often presented through metaphors, but little is known about the impact of such metaphors. Two experiments were conducted in Belgium presenting federalism as Tetris – with control and treatment groups – in order to grasp the influence of this metaphor. The first experiment reveals that being exposed to text with the Tetris metaphor influences respondents’ representations of federalism towards a more institutional representation and towards more regional autonomy. The second experiment confirms the importance of the text, and more specifically of the metaphor, if political knowledge is taken into account. Respondents with a lower level of political knowledge are those who are influenced by the metaphor, whereas respondents with a higher level are not. Therefore, framing the future of Belgian federalism using the metaphor of Tetris does matter: it affects both individuals’ representations of the federalization process and, consequently, their preferences vis-à-vis the institutional future of the country.