Answer:
You can read it both ways, I wearΝΎ One way it's a number, reversed a snare.
Who is he that runs without a leg. And his house on his back?
There is someone, and there is always another, for without the other, there wouldn't be one
Put into a pit, locked beneath a grate, guarded through the night, yet it still goes out.
A mile from end to end, yet as close to as a friend. A precious commodity, freely given. Seen on the dead and on the living. Found on the rich, poor, short and tall, but shared among children most of all.
People take me on walks and I run and have fun. What am I?