World map. I got a 4x8 sheet of half-inch plywood cut into thirds at Home Depot to end up with 3 pieces of 32x48" -- a good size to fill the empty wall in the dining room. With one-inch spacing, it gave me 32x48 pixels. I scaled down a world map to that size and posterized it to 5 colors (white + 4 shades of gray).
Adorably useful small wooden candle. Combining a space exactly of the size of the most common match box it shows a very intuitive way of using it. Tell me you don't want one and I will not believe you.