I had a piece of poplar cut into a rough hexagon with the chainsaw which was deeper than my normal blank, as mostly I cut slabs two to three inches (50 - 75 mm) thick that fit my bandsaw. I decided to try a bowl that came in quite a bit at the top, and having done that I felt it needed a lid.
I chose a piece of highly spalted poplar for the lid which gives a dramatic contrast. Both lid and bowl will change shape slightly, that's the nature of wood, so the fit isn't perfect. When I have some well seasoned stuff I may try one of those.