On my Excel courses I often show students how to add text boxes to worksheets and how to use 'Shapes' to annotate charts. I might even show them how to edit shapes by adding and deleting 'nodes'. Although we could easily spend many hours exploring shapes, I encourage them to 'play' with the shapes in their own time. However, recently I was quite blown away when I discovered Excel 'Art'. Now in his mid 70s, Tatsuo Horiuchi is a Japanese artist who found his passion in digital art using Microsoft Excel. Although he had never used Excel at work, he nevertheless soon mastered the technique and even won the Excel AutoShape Art Contest in 2006.
If you don't believe me, visit this link and download one of his pieces of work in Excel. Although it's quite a large file size, I believe you too will be blown away. You'll see that the artwork can be ungrouped many times - eventually down to individual petals. Wonderful!