Complex sentence: The effect was created by filming a long stick with a luminescent ball on the tip, which was physically "bounced" across a screen of printed words by a studio employee; the movement was captured on high-contrast film that rendered the stick invisible.
Split into simpler sentences: The effect was created by filming a long stick with a luminescent ball on the tip, which was physically "bounced" across a screen of printed words by a studio employee. The movement was captured on high-contrast film that rendered the stick invisible.