I start as sap from forest veins, then heat transforms my polymer chains. I stretch, return, and still endure, made strong and flexible through fires cure.

I make people cry But don’t live in a swamp I have many layers I’m not Donkey’s cake or parfait What am I?

Small and round, yet worth I hold, passed through hands more times than told.

Grown-ups might think I’m clutter on the floor, but to a child, I am so much more. A doll, building blocks, play-doh, yo-yos... we travel the world where imagination flows.

A time when I'm green, A time when I'm brown. But both of these times, Cause you to frown. But just in between, For a very short while. I'm perfect and yellow, And cause you to smile. What am I?