The real purpose of this post is to demonstrate the benefit (that is, the relative speed) of using C# code via COM Interop from VBA. However, if you find the Mandelbrot Set interesting then you can skip the C# code and explore the Mandelbrot Set using VBA only (but you'll explore it a lot faster if the download the C# code).
If you don't know what the Mandelbrot Set is, see this Wikipedia article - some example images produced by the Mandelbrot Set viewer (see download instructions below) are ...
For detailed instructions on how to use your own C# code from VBA for your projects, see my Calling C# code from VBA (COM interop) blog post.
Download and use the Mandelbrot Set viewer
Ensure you have .NET Framework 4.8 installed (it is installed by default with Windows 10 and 11). Download the mset.zip file, unblock it (if you're not sure how to do that, see my blog post Unblock a file containing VBA code), unzip it.
Follow the instructions in the 'READ ME.txt' file. Installing the C# library is optional. Works on Windows devices only.