Sample refactoring

I made a small change to help code organization.

I pulled out char_list into a method, instead of having it be an instance variable set at initialize time. This will also helps future refactorings.

You should consider whether to do the same for others For instance, I don't know what `@dwell` is. It might be something that a user can modify in later iterations of the code, and if so, it should stay in the initializer.

I also noticed what I think is a coupling: you depend on the order of the char_list to set the correct character. You might benefit from setting each of those characters as a special name and then using that name in the code when you need to. The downside of that, of course, is that it'd make the code larger, and maybe it doesn't need to grow any more than this.

One thing you should consider doing is find a way to add tests; the Ruby community is pretty big on tested code. Thankfully you have separated the display code from the logic, that'll make things easier.