Mathematics is not all about numbers on a page. Architects, engineers, artists, product designers, and others use planar and spatial geometry constantly. Most children use planar and spatial geometry every day! There are many things we just don’t think about in terms of mathematics, but intuitively interact with and understand them. Learning about solid shapes is a first step into understanding three dimensions and spatial reasoning, as well as more complex topics such as mass, weight, volume, density, positions in space, translation, rotation, revolution, forces in physics, and so many others.