Despite GUI applications having been around for 30ish years, software is still written as lines of text instructions, for various valid reasons. But we've also found that manipulating these text instructions is mind-blowingly difficult unless we apply a layer of coloring on different words to represent their syntax, thus allowing us to quickly parse through these text files without having to read the whole words.

But besides the Sublime Text minimap feature, I've yet to see any innovation in visual representation of code since colors came around on CRT monitors.

I can think of one obviously essential representation that modern graphics technology allows: visual hierarchies for nested structures. If we make nested text slightly smaller than its outer context, and zoom on it when the cursor is focused on the line, then we will be able to browse huge files of nested statements very quickly. This becomes even more essential as languages based on closures and anonymous functions become filled with deep statements.

Has anyone attempted to implement this in a text editor? Do you know of any otherwise useful improvements in representing code text graphically?