Used as a means of brainstorming, thumbnails can be an excellent tool. I use them to explore a concept or doodle in order to focus and challenge myself. Some days when I feel really frustrated by the artistic exercise, it’s a stretch to fill all of sections of the grid. If I push just a little bit harder and am outside of my comfort zone an idea will form for a larger piece and I can work on refining it further. Often times the abstract themes evolve from cell to cell by adjusting a line here or there which will lead to another idea which will grow into a much larger idea of what next to pursue. Some days however, the finished product is just a croweded page. Perhaps something to look back on later when starved for material. I find it fun to see a marked progress from the beginning to end, and a small victory over my own sloth when it’s completed. Perhaps you may find the concept useful for yourself!