This is an old tale which has changed over the years I have told it.
Nyame is a West African sky god and the tale begins in the darkness of empty space. Nyame opens a trapdoor and lets down a woven willow basket on the end the rainbow to swing in space. When the trapdoor is open the basket is lit by the light of Nyame’s eyes and when it is shut little lights shine through the knot holes in the trapdoor. Sun and Stars!
Nyame drops different clays into the basket, their tears and seeds. A beautiful garden grows in the basket swinging gently at the end of the rainbow.
Two spirit people come up from Nayame’s belly to peer out of their mouth into the basket. Pollen from the flowers makes Nyame sneeze and the spirit people fall into the basket. They explore and make little creatures / people from the different clay. They light a fire and put their creations around it. When Nyame climbs down the rainbow to investigate the spirit people try and hide their creations but ouch the fire is hot.
People what have you doing?
Nothing!!!
Are you sure?
Certainly … ah ah ah
Why are you making that noise??
Eventually they show Nyame the clay people which are all the different colours of the clay. Nyame breathes on them bringing them to life. That it why the world is full of people with different colours of skin.
In some versions of the story the clay people have different colours of skin because for the different times they have stood next to the fire. I prefer to have the colours coming from different colours of clay which allows for links to the different soil types.
The Fire Children: A West African Folk Tale by Eric Maddern is a good source

Creative Storytelling