Answer:
There is someone, and there is always another, for without the other, there wouldn't be one
Thirty white horses on a red hill, First they champ, Then they stamp, Then they stand still.
Sleeping during the day, I hide away. Watchful through the night, I open at dawn's light. But only for the briefest time, do I shine. And then I hide away. And sleep through the day.
What has 3 feet but cannot walk?
I'm tall in the morning and short in the noon. I disappear at night but I will be back soon.
People take me on walks and I run and have fun. What am I?