Myr Welder + Voltaic Construct + Gilded Lotus

Myr Welder

Voltaic Construct

Gilded Lotus

How it works

1. Activate Myr Welder using Gilded Lotus's ability by tapping it, adding three mana of any color.
2. If Voltaic Construct is on the battlefield, activate Voltaic Construct by paying 2, untapping Myr Welder. Otherwise, activate Myr Welder using Voltaic Construct's ability by paying 2, untapping Myr Welder.
3. Repeat.