How do I tell my opponent they're dead? (with Aftermath Analyst loops)

      Picture this: your Scapeshift is on the stack with four lands and one Amulet of Vigor on the field. You know your opponent has no interaction, and, accordingly, they tell you it resolves. “I win,” you smugly inform them.
      Their eyebrows furrow. “Huh?”
      With an audible sigh, you roll your eyes and move the four lands to the graveyard. You grab your deck and search out two copies of Lotus Field, one Simic Growth Chamber, and one Tolaria West - Japanese nonfoils, of course - and silently gesture towards the lands on the field.
      “So you’re going to be able to transmute Tolaria West?” Your opponent manages to cobble together.
      A broken clock is right sometimes, you think to yourself as a smirk forms. Heh. Broken clock, like the Ragavan that couldn’t kill you. “Float 9 pick up T West sac everything, transmute for Pact Analyst and crack.” You stare at your opponent.
      “Uh, sure, that’s fine.”
      “Bounce Twest get Pact get Titan get Woodland and loop you. I win.”
      “Sorry, can you slow down? How do you win?”
      You exhale an even deeper sigh. “I make infinite mana and then make infinite Titans and then Haste all of them, and I’m also going to hit all of your permanents with Boseiju and Otawara too, then swing for a billion.”
      Your opponent’s eyebrows haven’t unfurrowed since you started gesticulating at the table five minutes ago. They extend the hand. “I guess I can’t do anything about that. Good games.”
      “I guess,” you mutter as you limply reciprocate with your hand.
      Soon after putting the results into the Magic Companion app, you look at your standings: 2-2, with the worst tiebreakers. 9th place. No FNM promo pack, no store credit. “Bullshit”, you think as you storm out of the LGS. “I got so unlucky. I had the correct Explore/Rumble split. I had the optimal 61.”

Why should I care?

Silly vignette aside, FAR too many Amulet Titan pilots, both old and new, are guilty of poorly communicating their Aftermath Analyst combo kill. Although many competitive players will scoop at the point that you have the board state set up, no opponent is obligated to concede. Therefore (and this should go without saying), you should never be rude/antagonistic if your opponent asks you to play it out. At best, they might have some interaction, or, at worst, they want to skill check you. No matter what, you should be ready to clearly communicate your game actions. This will save you clock time and confusion.

Note: This is written with the expectation that you are already familiar with the Aftermath Analyst combo with Shifting Woodland. This is not intended to be a beginner-friendly explanation of the combo itself, but this document will touch on many of those details. If you are unfamiliar with the combo and/or getting to the Analyst looping game state (e.g. via Scapeshift lines or Titan + 2 Amulet lines), refer to the “Aftermath Analyst” and “Scapeshift” sections in Dom Harvey’s encyclopedia, hyperlinked.

Explaining the Aftermath Analyst combo

Explaining and performing the game actions that you will execute to win the game by Analyst looping can be broken into one prerequisite and three high level steps:

0) Set up your board to Analyst loop
1) Perform one iteration of the loop
2) Generate infinite mana
3) Infinite land activations

While this guide is more detailed and comprehensive, it is approximated to this verbal explanation in-person:
“I will use 8 mana to have Woodland copy Analyst then crack Woodland-Analyst for two Lotus, Forest, Saga, and the Woodland itself. These lands make 9 Mana. If you have no responses, I'm going to repeat this for infinite Mana of each color and colorless.
Then, I'm going to add in sacrificing Mirrorpool to copy Titan for each loop. Then, Titan will grab a Hanweir. I’ll haste a Titan, then sacrifice Hanweir instead of Forest for each loop, letting me haste all of the Titans. Swing for lethal?”

Step 0. Set up the board

This step may sound trivial, but it is important to be clear the distinction between the game actions taken to set up the board, and the actual loops; both involve similar steps. Activating Analyst, transmuting Tolaria West, activating Urza’s Cave, etc. can be used to set up the board to loop with Shifting Woodland, as well as later be used to convert a “loop” into a kill.

In short, your board should have Shifting Woodland and an Amulet effect(s) on the battlefield, Lotus Field(s) and Aftermath Analyst in the graveyard, 8 mana floating, and Delirium achieved.
If you have not met these minimum requirements, you likely do not have a deterministic loop that can be shortcut by Magic rules (and you are probably still setting up the board to get to this point).

Step 1. Perform one loop

1) Verbally note how much mana you have floating.
2) Activate Shifting Woodland, targeting Aftermath Analyst.
3) Sacrifice your Analyst copy to return Lotus Fields, Shifting Woodland and any other lands.
4) Float your mana, then sacrifice your lands to Lotus Field triggers.
5) Once again, verbally note how much mana you have floating.

Step 2. Loop infinite mana

1) Based on Step 1, inform your opponent you intend to repeat this loop a large number of times.
2) Each loop will generate infinite of a given colored mana by Lotus Field.
3) Each loop will generate infinite colorless mana by sacrificing a colorless-producing land.

Step 3. Loop infinite land activations

1) Inform your opponent that with infinite mana, you will now begin to loop with specific land activations/abilities from the lands sacrificed alongside Lotus Field.
2) For infinite ETBs, copy a land from your or an opponent’s graveyard with Echoing Deeps before sacrificing it to Lotus Field for each loop. Surveil Land nets “Mill 1” for each loop iteration, allowing you to get to any of the game states below.
3) For infinite creatures, activate Mirrorpool to copy a creature with each iteration of the loop.
4) For infinite activated abilities, activate the land before sacrificing it to the Lotus Field for each loop. E.g. haste with Hanweir Battlements, Urza's Cave to fetch any land, Ghost Quarter opponent’s lands, etc.
5) For infinite Tolaria West/Boseiju/Otawara activations: sacrifice Bounceland to Lotus Field, then bounce and activate Tolaria West for each loop.

What is a “loop”?

The definition from the Magic Tournament Rules (MTR), section 4.4, defines a loop as “a form of tournament shortcut that involves detailing a sequence of actions to be repeated and then performing a number of iterations of that sequence”. (We often say “infinite” but technically choose a finite number to arrive at a known game state. For cool number theory facts, please consult someone else and tell me what you learn.)

In the detailed explanation above, Step 2 is all about explicitly informing your opponent that you are going to use this shortcut. They can stop you at any point before the entire iteration of a loop is completed, such as casting Surgical Extraction after you activate Shifting Woodland targeting Analyst. But, critically, if your opponent doesn't have any responses, they cannot ask you to do the repetition one by one. Call a judge in this scenario. Likewise, YOU cannot choose to do these repetitions one by one. Per the MTR, “A player may not ‘opt-out’ of shortcutting a loop, nor may they make irrelevant changes between iterations in an attempt to make it appear as though there is no loop.”

However, many Titan players confuse this rule about loops with trying to go from Step 0 all the way to the final results of Step 3. You are allowed to let your opponent know what you plan to do across several steps, but this is not a rules-defined shortcut despite, yes, including loops in the middle of those steps. If your opponent asks you to play it out, do the individual loops; i.e. loop to make all the mana, then loop to make all the titans, then loop to haste all the titans, etc. You should do so with clarity out of respect for your opponent, and, in doing so, you also have the MTR (with judge’s help) if you face any bad actors who try to stall.

In closing

Don’t be an asshole. Know how to, and be willing to, play out your deck, and do it clean. If you can't clearly explain it, practice until you can - for your sake and your opponent's. You will save yourself, your opponent, and all of the other tournament attendees clock time. Good luck, gamer.
(Was this just a means to publicize the worst display of humility in all of Magic history in the prologue? I’ll never admit it.)