# Alien Autopsy Solution

## How It Works

The goal of the puzzle is to balance the alien's "life force": the cards attached to each of the "organs" in the alien's body. This requires teams to do three things more or less in parallel: Play Operation to remove the organs, solve a weighing puzzle to determine which card has which weight, and solve a balance puzzle to determine where the cards belong. Once they do those things, they put the cards in the right organs and play Operation again to put them back in the body.

The "surgery quality bar" is a life bar that ties the aspects of the puzzle together: it goes down whenever they touch the edge in Operation or perform a weighing, and regenerates slowly over time. So the better they are at Operation, the more weighings they can make, and vice versa. When the bar reaches a sufficiently low level, the proctor prevents the teams from interacting with the device.

### Operation

The Operation stage works like the game but bigger: teams have a pair of tongs to remove or replace the organs from the alien body, without touching the foil-lined sides and completing the circuit.

### Weighing

The teams are given a Bloid Comparison Device, which takes two cards. How it works isn't explained, but it's pretty simple: it displays the difference between the values of the two cards with no feedback of which one is heavier. With four or five weighings, and the information from the handouts of what the possible weights are, teams can identify all the weights.

### Balance

This is a two-dimensional balance puzzle: teams need to find a way to arrange the six weights such that the center of gravity is in the "origin" of the axis lines drawn on the body. The cleanest way to do this is to make the x and y components balanced. The only trick is that, since the "head" is two units away from the origin, you have to double its contribution to the y axis. Otherwise, the y axis will be trivially unsolvable. (You would need two components that have the same sum as three other components, and the largest two sum to more than the smallest three.)

A good starting point is to look at how to balance the x axis: find two pairs of weights with the same sum. There are two ways to do this: 15+22 = 16+21 and 16+27 = 21+22. From there, you can balance y by trial and error; an intuitive leap is to put the lightest weight at the "head", which is correct. The correct arrangement is: (with the * at the origin)

15
21*
2219

(2*15 + 27 = 22 + 19 + 16, and 22 + 21 = 27 + 16)

When the life force is properly arranged, the device will give teams the answer MALPRACTICE.

MALPRACTICE

## Design Notes

Ben wanted to do an Operation puzzle, but didn't have a good idea for the puzzle part. Greg contributed that piece, (for his second "provide puzzle mechanic for somebody else's technology" this Game) with inspiration from Trauma Team, among other places.

## Construction Notes

Matt stepped in with the physical construction and totally nailed it; the chain intestines in particular were a stroke of genius. Ben handled the electronic side, wiring up the buzzer and RFID readers as well as constructing the tongs.

fun fact: due to last minute time constraints, each table had a separate laptop; originally, a single laptop was planned to drive all five instances. There's no feeling of trepidation quite like plugging 40 RFID readers plus ten USB hubs and 5 Arduino Leonardos in via a single cable.

## GC Notes

Notable performance in this puzzle could earn two achievements: "He's dead, Jim" for hitting the flatline state, and "I threw it on the ground!" for, well, that.