Geometry is the branch of mathematics that addresses spatial sense and geometric reasoning. Students begin to understand geometry through direct interaction with their physical world. Because it is the study of the physical attributes of the environment, geometry has relevance for every student; the world becomes a big classroom. As students see, touch, and manipulate shapes, they begin to develop spatial reasoning skills. Although geometry is an integral part of the curriculum, many students fail to develop a deep understanding of basic geometric concepts. According to the National Council of Teachers of Mathematics (NCTM 2000), K-grade 12 geometry instruction should empower students with the ability to analyze properties of geometric shapes and to base sound arguments on the understanding of relationships among these properties. Kindergarten students should be able to "describe attributes and parts of two-dimensional shapes" (NCTM 2006, p. 24). Geometry instruction at the primary level is best facilitated using concrete models, drawings, and dynamic software as appropriate. This article will discuss activities that are designed to use attribute blocks to facilitate students' development of spatial reasoning skills. The Van Hiele theory offers a framework for reflecting on these activities and their instructional value in fostering deep geometric understandings for students.