Retrofitter Foundry's fourth ability by tapping it and sacrificing a Thopter, creating a 4/4 Construct artifact creature token, a 1/1 Thopter artifact creature token, and a Food token.
Activate
Urza's first ability three times by tapping the Thopter, Construct and Food, adding ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Activate
Retrofitter Foundry's first ability by paying ({3} magic symbol) , untapping it.