How was the tire discovered?
Charred remains of wood and bones have been found from the caves showing that fire was known to man in the stone age.
Probably a bolt of lightning must have struck a dead tree setting it on fire. Early man must have lit a fire from this and kept it burning for a long time in his cave. A fire initially out of fascination later for its uses would have illuminated the cave provided warmth to him and kept the wild animals away. Food cooked in fire was more tasty and last longer.
Discovering how to start a fire by himself must have an accident while walking on the stones at night. He must have noticed sparks coming out when one base stone struck another.