Interactive geometry software
Polyhedron is an MS DOS application based on a practical approach to solid geometry. It allows the user to perform various actions upon solids as if holding them in hands.
Polyhedron simulates a number of tools, such as ruler, protractor, setsquare, compass, bisector, saw, eraser, all accessible from a menu bar. Solids can be revolved, displayed in different manners, cut.
Polyhedron is packed with 250 built-in problems. You may be surprised by what some of them deal with. There are problems about frameworks, toys, beetles, other improbable stuff. The problems of complexity 5-6 (there are 6 complexity levels) have proven difficult enough even for the smartest undergraduate students.
Polyhedron was built on the carpenter workshop philosophy. You can read more about it here. The note also contains sample problems with resolutions.
Geometria is a Java upgrade to Polyhedron.