Poleidoblocs are the coloured building bricks introduced by Dr Margaret Lowenfeld some 55 years ago, yet still sustain their popularity in many primary school classrooms. Many of the aims and opportunities for mathematics learning outlined by Dr Margaret Lowenfeld herself are as valuable as they ever were. Mathematical understanding of relationships in sorting, balancing and measuring, as well as of the characteristics of structures and 3-D shapes, appear to relate well to many requirements of the National Curriculum.