Ahh.
And upon not being lazy and looking at the C, I see this...
ary2 = ary_new(rb_obj_class(ary), len);

Which I'm guessing is equivalent to this in ruby (which I already knew
would return the same array len times)
ary2=Array.new(ary,len)

Any chance the document maintainer could slip the word "shallow" into
the description of array*?

:)