This fruit looks like an octagon. When I was a child, I put a toothpick in the middle of the fruit and could turn it on the ground. What's the name of this fruit tree?

Qinggang Tree, a deciduous or evergreen tree, has yellow-green flowers in May. The flowers are monoecious, and the male flowers have catkins, which are slender and drooping. Nuts are oval or ovoid, born in cup-shaped shells and mature in 10. Leaves will change with the weather, so they are also called "weather trees".

Cyclobalanopsis glauca, whose real name is Cyclobalanopsis glauca, has other aliases: Quercus purpurea, Castanopsis fargesii, Elaeagnus tenuifolia, Quercus acutissima and Iron Monkey. Latin name Cyclobalanopsis glauca. ) Oster. An evergreen tree of FAGACEAE. As an important part of evergreen broad-leaved forest, it is barren-tolerant and likes calcium. Wood has excellent properties and is an important material for making wooden shuttles in textile industry.