Changed this a little to make some areas a little darker and a couple a little lighter. Hope it comes across a little stronger.
Copic Sketch Markers
Airstreams are my favorite
So why not use them as an example of how to add detail and then add gray scale. Not so sure the gray scale is working as well as it could. May have to do over, but my printer decided not to work today. So maybe tomorrow.
Frank Lloyd Wright Falling Water
In these two drawings you can see the difference adding gray using Copic Sketch Markers make in the finished drawing of Falling Water.
The first drawing works but the second is much more dramatic and hopefully catches your eye by using more drama.