If Flame Jab is in your graveyard, cast it for its retrace cost by paying ({1} magic symbol) and discarding a basic land card, targeting Polyraptor.
Otherwise, cast it by paying ({1} magic symbol) , targeting Polyraptor.
Resolve Flame Jab, dealing 1 damage to Polyraptor.
Polyraptor triggers, creating a token copy of itself.
The Polyraptor token enters the battlefield, triggering Mana Echoes, adding ({C} magic symbol) for each Dinosaur you control.
If you cast Flame Jab from your graveyard, activate Groundskeeper by paying ({2} magic symbol) , returning a basic land card from your graveyard to your hand.
Repeat.
Once you have infinite mana, you may instead target any other target using Flame Jab.