Myr Welder + Magistrate's Scepter + Gemstone Array

Myr Welder

Magistrate's Scepter

Gemstone Array

How it works

1. Activate Myr Welder using Gemstone Array's first ability by paying 2, putting a charge counter on Myr Welder.
2. Repeat step 1 two additional times.
3. Activate Myr Welder using Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, causing you to take an extra turn after this one.
4. Repeat each turn.