Cubism and "Cabri"

Prague, as many people will know, is a beautiful and very accessible city with many architectural gems. One of its lesser-known features is its architectural link with cubism. These include a remarkable streetlamp hidden in a small square, Jungmannovo namesti, just a stone's throw from the main Mustek metro station at the top of Wenceslas Square (Vaclavske namesti). This article illustrates some of the ways in which teachers can use dynamic geometry software, such as "Cabri 3D" and "Cabri II Plus," to help model structures both to give good fits to images taken from photographs and to perform analyses on them using measures, scales and calculations. (Contains 7 figures and 2 notes.)