Honeybees

There are several large sunflowers in the yard.  Honeybees have been recorded collecting the nectar starting from the center of the flower and going around in a circle.  I was wondering why the center had these perfect circles in them.  I think these three are the same flower a day or two apart.  The bee's legs are full of the yellow stuff.  They got a little miffed when I zoomed in the lens and got close enough to disturb them.  After eating the nectar, the seeds are exposed.  When the seeds get harvested and dried, the birds will be happy come winter. Another wonder of God's creation.