CS1 Course Site       Compilation of Powerful Ideas ( Cognitive and Computational ) Top 10 list of Powerful Ideas Classes   Classes are a powerful idea in that,  they save programmers time,  and space (in their programs). A class is a set of objects grouped togeather. Without classes programmers would have to write,  for instance,  everything in the circle package,  in each program they wrote,  every time they wanted to create,  and manipulate circles.