Answer:
I am always coming but I never arrive. What am I?
I am needed for most animals and hardcover books. What am I?
I can be simple or I can be complex. I can be found in this riddle or in everyday life. I can be shapes or even colors.
I have leaves on my fruit my fruit is on my leaves.
Used left or right I get to travel over cobblestone or gravel. Used up I vie for sweet success used down I cause men great duress.
If you count 20 houses on your right going to the store and 20 houses on your left coming home, how many houses did you count?