Three by three--because it isn't nice to hurt a tree
Four by four--To hew the stone and break the door
Five by Five--and Saurman will not long survive
Six by six--Because someone turned their friends into sticks.
Seven by seven__and I don't think orcs go to heaven
Nine by nind--Merry and Pippin are feeling fine.
Ten by Ten--To the aid of the Rohan men.

My appologies to admirers of J.R.R. Tolkien, and lovers of good music everywhere, and to trees too.