They built a rotor with two permanent magnets on it, and they made an electromagnet by winding copper wire around a large nail.
(They; built; a rotor) (they; made; an electromagnet) Context(they made,List([57, 66))):(they; made an electromagnet by winding; copper wire; around a large nail)
they made,List([57, 66))
They they they
built made made an electromagnet by winding
a rotor
an electromagnet
copper wire around a large nail