Greetings kelley1 -
Thanks! 
. Most of my projects start off based on something I want to learn or a new material / technique I want to try, and a loose kind of feature set / theme I want it to have, like the Aquarium project. Then I just start, and let it grow organically until I run into some limitation, be it in cost, materials, physics or my skill set (usually). 
Sure, sometimes one will burn whole in my pocket, or end up going down in flames 
and I write it off as a learning experience. But occasionally one becomes a real barn burner, like this one. It becomes so satisfying to see it form, I’ll even burn the midnight oil working on it.
HL