Sketchup is an architectural application that you can download for free from the internet. If you would like, you can spend the $500 on the sketchup pro, which I only suggest if you are an architect. In the plain sketchup, as of Sketchup 8, you can create just about any building you would like. You can use a circle, square, rectangle, or create your own shape. You can use a height tool to make a block.
At the start, you choose a template, and then you begin. You can choose from a plain architecture with feet and inches, or do another with meters. Once you begin, there will be a person, so that you can scale your creations. If you delete that person, you can just use the ruler tool to find out the dimensions. I won’t show you one of my creations, but below is a picture from flickrcc about a creation.
Sketchup is one of the coolest programs I have ever seen. I am really interested in architecture. Maybe sometime we can work together on a sketchup to make something. Great post, Gus. Sketchup is awesome.