Answer:
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 run through hills. I veer around mountains. I leap over rivers. And crawl through the forests. Step out your door to find me.
I am a seed with three letters in my name. Take away the last two and I still sound the same.
I have feet on my head
I am lighter than air, but a hundred people cannot lift me. Careful, I am fragile. What am I?
They're actually great swimmers now, but later they will become excellent hoppers.