All permanents on the battlefield (Leyline of Transformation with "Sliver" chosen).
Steps
Cast Ornithopter by paying ({0} magic symbol) , and choosing to pay its replicate cost an arbitrarily large number of times by paying ({0} magic symbol) .
Ornithopter triggers, creating a copy of it for each time its replicate cost was paid.
Resolve all Ornithopter spells, causing the nontoken Ornithopter to enter the battlefield, and creating a token copy of it for each time its replicate cost was paid.