In Montessori classrooms, "work" means so much. For starters, it's all about the process, instead of the product. About developing rhythms, habits and consistency, repeatedly practicing with that which will help you grow. For instance, just because you accomplish a task one time, doesn't mean that you instantly have the activity mastered, no matter how great you are - and, we know you are awesome.
By working with the same activity over and over, children find new ways to improve themselves. There are layers to absolutely everything that we do: essentially, building the foundations for later, more extensive applications. Take, for example, the metal insets, demonstrated in the video above. The first objective of the activity is to carefully trace the inset, making an outline on the paper, then filling in the rectangle.
There are many variations to this specific activity, but you'll immediately notice his fine motor skills, diligintly working, concentrating on keeping the colored pencil marks precisely within the outline. While this is creating discipline, order, focus, determination, etc, it's also helping refine his ability to hold and utilize a pencil, which will become increasinly important for handwriting.