In the current elementary school curriculum, little attention is devoted to developing students' geometric problem solving abilities, spatial thinking, or ability to analyze and reconceptualize substantive geometric ideas. Use of the Logo computer language has the potential of transforming both the content and method of the elementary school geometry curriculum. This project will develop a new geometry curriculum for use in elementary schools and will create a set of Logo based classroom activities that promote the objectives of the curriculum. Expected outcomes will include a set of instructional materials, a book for teachers, recommendations for teacher training, and a videotaped program that will include exemplary lessons taught by teachers involved in the field test.