Abstract This chapter focuses on digital technologies and geometry education,
a combination of topics that provides a suitable avenue for analysing closely
the issues and challenges involved in designing and utilizing digital technologies
for learning mathematics. In revealing these issues and challenges, the chapter
examines the design of digital technologies and related forms of learning activities
for a range of geometries, including Euclidean and co-ordinate geometries in two
and three dimensions, and non-Euclidean geometries such as spherical, hyperbolic
and fractal geometry. This analysis reveals the decisions that designers take when
designing for different geometries on the flat computer screen. Such decisions are
not only about the geometry but also about the learner in terms of supporting their
perceptions of what are the key features of geometry.