Complex sentence: The poem, which was produced between 1804 and 1820, consists of 100 engraved and illustrated plates, using Blake's self-devised technique of "illuminated printing".
Split into simpler sentences: The poem, which was produced between 1804 and 1820, consists of 100 engraved and illustrated plates. The illustrated plates were made using Blake's self-devised technique of "illuminated printing".