Riddle me this

So, Ashley got a book of riddles from the library, and Sunday morning we sat around trying to figure some of them out. Fun way to spend an hour. But I gotta' say there were a few in there that made me raise my eyebrows. This one for example, I wouldn't even try to figure out. I was like, "just give me the answer already, that's way too ridiculous!!!"



So, let me know what you think the answer is.....there might be something in it for ya'!



Two legs was sitting on three legs holding one leg,

Along came four legs and seized one leg,

So two legs picked up three legs and threw it at four legs,

And four legs brought back one leg.



What do you think ?
Of course, now that I'm looking at it, knowing the answer, it seems obvious. But when Ashley read it to us, it seemed impossible to figure out.