These materials were produced by the staff and the students of the Laboratory of Eidomatics, with support from the MURST, CNR, EEC, HP Corporation. We welcome comments and suggestions, which may be forwarded to marini@eidomatica.dsi.unimi.it . Educational institutions are encouraged to reproduce and distribute these materials for educational use as long as credit and notification are provided. Please retain the copyright notice and include this statement with any copies that you make, and send notification of their use to marini@eidomatica.dsi.unimi.it. Commercial use of these materials is prohibited without prior written permission.