Okay, I'm trying to find a program for doing design visualization. Similar to UML, but less complex, not so low-level. When I start working on a new design, I tend to visualize the program components in my head as boxes, boxes within boxes, boxes connecting to boxes, etc. A very simple way of quickly seeing all components of a program, how they're broken down, and how they interact. However I've been unable to find a decent program that lets me quickly draw this on the computer, to refer back to later. Things like UML tend to get me bogged down in the details of using UML itself, rather than just giving me a few basics to quickly draw the idea out. I hope I'm clear in describing this. Does anyone know of some possible programs that can do this?

Pencil and paper is certainly a last resort option, and one that I've used in the past, but the main downside is that you can't very well hash out ideas on paper, like moving things around or redesigning a component, without redrawing from scratch. A program would let you accomplish the same thing without being permanent, laying out your components and connections and still having the freedom to change it as you add detail.

I haven't yet found the perfect solution, but I have started using gModeler, which is a very simple (online, free) UML program. Rather limited in features, but it definitely has allowed me to dive in and work some things out without a learning curve.