Solution to the building challenge

Here are the steps to complete the complex building challenge:

1. Create a very tall cube for the body of the building.
2. Add another cube. Scale it up so it is wider than the first cube, then scale it down on the Z axis to make it thin.
3. Move the thin cube down on the Z axis so that it is at the base of the tall cube. We will now use an Array modifier to duplicate it upward and create the rest of the thin cubes.
4. Add an Array modifier to the thin cube. Change the offset setting on the modifier to 0 for X and Y and 1.8 for the Z value.
5. Turn up the count on the Array modifier to increase the number of thin cubes.
6. Once you’re happy, apply the modifier to make it permanent, then move the stacked-thin-cubes object upward so that the very top thin cube looks like a roof on the building.

Done!