patty-cake

a variation of pat-a-cake, a children's game played by a child clapping hands alone and with another child while chanting a nursery rhyme which has the following beginning words:

"Pat-a-cake, pat-a-cake, baker's man!
Bake me a cake as fast as you can,
Shape it and prick it, and mark it with B,
And put it in the oven for Baby and me!"

Figuratively used to mean "childish clarity or simplicity".