Katsumasa and Voltaic Construct on the battlefield.
You control a noncreature artifact that does not have summoning sickness and can tap to produce at least ({3} magic symbol) .
({1} magic symbol) ({U} magic symbol) available.
Steps
Activate the mana-producing artifact by tapping it, adding at least ({3} magic symbol) .
Activate Katsumasa by paying ({2} magic symbol) ({U} magic symbol) , causing the mana-producing artifact to become a 1/1 artifact creature until end of turn.
Activate Voltaic Construct by paying ({2} magic symbol) , untapping the artifact.
Activate the mana-producing artifact by tapping it, adding at least ({3} magic symbol) .