Myr Welder and Biotransference on the battlefield.
Empowered Autogenerator and Gilder Bairn in exile (exiled by Myr Welder).
Myr Welder does not have summoning sickness.
({1} magic symbol) (at most) available.
Steps
Activate Myr Welder using Empowered Autogenerator's ability by tapping it, putting a charge counter on Myr Welder and adding ({G} magic symbol) or ({U} magic symbol) for each charge counter on Myr Welder.
Activate Myr Welder using Gilder Bairn's ability by paying ({2} magic symbol) ({GU} magic symbol) and untapping it, targeting any permanent.