1. Take a tape measure and go up to a brick wall on some house or building. Measure out 5 feet. Count the bricks. This will also include the mortor gaps
2. Now measure out 2 feet. Count the bricks.
3. select a layer and count up 3 feet. This will tell you how many layers of 2ft by 5ft by 3ft of bricks there are. The number of bricks wil vary depending on size of bricks you get.
4. I haven't heard the term "Cat House" in a long time... Adios... Jasper.