No problem and no need to apologise, keep at it
I think you could go a lot further; you're still using many small, consistently sized particles and just adding a highlight/column. Here's a rounded 'hunks' example with more variation and sense of form. Try thinking about form by working dark to light, starting really simply with a variety of shapes in midtones and adding flat shades by thinking about where light might fall on them.
If you really want to understand the idea thoroughly so that you can apply it in other situations I'd experiment, very roughly, with many different approaches. I edited my previous examples with another pattern too.