LEGO® stop-motion animations were developed to engage first-year university students in the topics of matrices, vectors, linear geometry and linear transformations. LEGO® provided a versatile medium through which a wide range of concrete and abstract concepts could be physically demonstrated in both two and three dimensions. It was also familiar to most students, making the mathematics videos accessible and fun. When designed according to key principles around reducing cognitive load in multimedia learning, animations in education have been shown to increase learning compared to static images for concepts involving dynamic systems and processes. Multimodal approaches including video and narration have also been shown to be beneficial to students in terms of demonstrating mathematical problem solving. The videos created in this project were a mix of conceptual explanations and problem-solving examples, where the word problems were physically modelled before being converted to formal mathematical notation and then solved. Some animations were short clips that were integrated into online lecture recordings, others were stand-alone videos designed either as short introductions to topics or examples of common questions. This paper describes the theory underpinning the design of the animations.