rotate

Returns a new array by rotating self so that the element at count is the first element of the new array.

If count is negative then it rotates in the opposite direction, starting from the end of self where -1 is the last element.

a = [ "a", "b", "c", "d" ]
a.rotate         #=> ["b", "c", "d", "a"]
a                #=> ["a", "b", "c", "d"]
a.rotate(2)      #=> ["c", "d", "a", "b"]
a.rotate(-3)     #=> ["b", "c", "d", "a"]