I’ve been dreaming of organizing code in two dimensions too. Maybe even three dimensions. But at least two. My own thinking is that perhaps with higher resolutions like we have now, and very wide screen monitors becoming popular, more people might start to look into organizing code in more spatial dimensions.
Your paned approach is very interesting. Seems more tidy than purely graphical node-based programming.
Now I am wondering if your approach could also lend itself to debugging code. Where you’d step through the code and each time you step into a function in the debugger it would open a pane with the code of the function to the right. And same for breakpoints so if you ran your code to a breakpoint then it would show each function in a pane organized horizontally corresponding to the stack trace at the point where execution was stopped.