Buckminster Fuller, in Critical Path (hello, Dr. Hoo!), answers a child’s query, “What is fire?”:

“Fire is the Sun unwinding from the tree’s log. The Earth revolves and the trees revolve as the radiation from the Sun’s flame reaches the revolving planet Earth. By photosynthesis the green buds and leaves of the tree convert that Sun radiation into hydrocarbon molecules, which form into the bio-cells of the green, outer, cambium layer of the tree. The tree is a tetrahedron that makes a cone as it revolves. The tree’s three tetrahedral roots spread out into the ground to anchor the tree and get water. Each year the new, outer-layer, green-tree cone revolves 365 turns, and every year the tree grows its new tender-green, bio-cell cone layer just under the bark and over the accumulating cones of previous years. Each ring of the many rings of the saw-cut log is one year’s Sun-energy impoundment. So the fire is the many-years-of-Sun-flame-winding now unwinding from the tree. When the log fire pop-sparks, it is letting go a very sunny day long ago, and doing so in a hurry.”