The Account Viewer allows users to deposit and withdraw funds from a single bank account. Here's a screen shot (withdraw field not shown):
Implement this as a customization of the above framework.
Here's a solution, don't peek: account.zip.
Brick CAD is a CAD system for designing bricks of different dimensions. Implement BrickCAD as a customization of the Simple Framework. Specifically, show how you would implement the Brick and Set Height classes:
Here's a test harness: BrickCAD.java