All other permanents on the battlefield (Mirrodin Besieged with "Mirran" chosen).
Steps
Cast Lotus Petal by paying ({0} magic symbol) .
Mirrodin Besieged and Displacer Kitten trigger.
Resolve the Mirrodin Besieged trigger, creating a 1/1 Myr artifact creature token.
Resolve the Displacer Kitten trigger, blinking Trading Post.
Activate Lotus Petal by tapping and sacrificing it, adding ({1} magic symbol) .
Activate Trading Post's third ability by paying ({1} magic symbol) , tapping and sacrificing the Myr token, returning Lotus Petal from your graveyard to your hand.