This study reports the results of an innovative assignment in which preservice teachers' mental representations were examined through drawing floor plans of an "ideal middle-level mathematics classroom." The 41 middle-level mathematics preservice teachers created two floor plans, one at the beginning of the semester and the other for the course final. An essay was also submitted describing how the final floor plan addressed the National Council of Teachers of Mathematics principle of Teaching. Participants designed and described floor plans that encouraged the use of inquiry and hands-on activities and technology as instructional strategies, focused on student learning styles and individual needs, established a comfortable, organized and safe learning environment, demonstrated flexibility in grouping strategies, and encouraged communication between peers and with the teacher. The essays also suggest that the preservice teachers' emerging teacher identity was influenced by professional experiences such as field placements and peer lessons. (Contains 3 tables and 3 figures.)