Walking in the woods I found the destroyed nest of a Paper Wasp colony.
You can see the gray and brown mixing beautifully here.
The nest is swathed in these sheets and blankets of paper to protect the cells inside. The cells are for brood rearing. They are perfect hexagons, just big enough for the queen to back into and lay an egg. This post from Hilton Pond Center explains that part beautifully.
I tried to insert a finger into one, but they were all too thick, including my pinkie.
Wasps build these nests in protected areas such as under the eaves of houses or in trees. I suspect this one was destroyed by humans and tossed into the woods as trash, but I prefer to think it fell from this pine during a windstorm.