Voltaic Construct + Karn, Silver Golem + Five Hundred Year Diary

Voltaic Construct

Karn, Silver Golem

Five Hundred Year Diary

How it works

1. Animate Five Hundred Year Diary using Karn.
2. Activate Five Hundred Year Diary by tapping it, adding for each Clue you control
3. Activate Voltaic Construct by paying 2, untapping Five Hundred Year Diary.
4. Repeat from step 2.

This clever loop centers around transforming Five Hundred Year Diary from a harmless noncreature artifact into an animated artifact creature using Karn, Silver Golem's second ability, allowing it to tap for blue mana based on your Clues. Once the Diary is a creature, Voltaic Construct can step in with its untap ability for just two mana, resetting the Diary so you can tap it over and over again. As long as you have enough Clues to generate more than two blue mana per activation—or a cost reducer—this engine yields infinite blue mana and infinite untaps for your artifact creatures.