Answer:
I drift forever with the current down these long canals they’ve made, Tame, yet wild, I run elusive Multitasking to your aid. Before I came, the world was darker, colder, sometimes, rougher, true. But though I might make living easy, I’m good at killing people too.
What flares up and does a lot of good, and when it dies is just a piece of wood?
A house of wood in a hidden place. Built without nails or glue. High above the earthen ground It holds pale gems of blue.
Of these things - I have two. One for me - and one for you. And when you ask about the price, I simply smile and nod twice.
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?