Golden Images (Solution) -- COINHEIST

by Lilly Chin and Jonathan Tidor

Identifying the pictures in each group, we get the following:

1	Train
2	Plane	Rocket
3	Kiss	Mother and Child
4	Wind	Solar System	Rain
5	Tool
6	Birds	Hyena	Continental Drift
7	Tame Dog
8	Tractor	Mitosis
9	Music of the Spheres
10	Cricket	Frog
11	Fire	X-Ray
12	Volcano	Earthquake	Traffic
13	Horse and Cart
14	EKG	Pulsar
15	Morse Code	Teacher
16	Anatomy	Sawing	Blacksmith
17	Mud Pots
18	Tractor	Bus	Solar Spectrum
19	Chimpanzees
20	Sun	Laughing	Heartbeat
21	Wild Dog

Google reveals that these pictures correspond to titles of sounds from the Voyager Golden Record in the Sounds of Earth section.

The sounds are:

1	Music of the Spheres
2	Volcanoes	Earthquake	Thunder
3	Mud Pots
4	Wind	Rains	Surf
5	Crickets	Frogs
6	Birds	Hyena	Elephant
7	Chimpanzee
8	Wild Dog
9	Footsteps	Heartbeat	Laughter
10	Fire	Speech
11	The First Tools
12	Tame Dog
13	Herding Sheep	Blacksmith	Sawing
14	Tractor	Riveter
15	Morse Code	Ships
16	Horse and Cart
17	Train
18	Tractor	Bus	Auto
19	F-111 Flyby	Saturn 5 Lift-Off
20	Kiss	Mother and Child
21	Life Signs	Pulsar

These groupings correspond to the groups of images albeit in another order. The correspondence is a follows:

1	17	Train
2	19	Plane	Rocket
3	20	Kiss	Mother and Child
4	4	Wind	Solar System	Rain
5	11	Tool
6	6	Birds	Hyena	Continental Drift
7	12	Tame Dog
8	14	Tractor	Mitosis
9	1	Music of the Spheres
10	5	Cricket	Frog
11	10	Fire	X-Ray
12	2	Volcano	Earthquake	Traffic
13	16	Horse and Cart
14	21	EKG	Pulsar
15	15	Morse Code	Teacher
16	13	Anatomy	Sawing	Blacksmith
17	3	Mud Pots
18	18	Tractor	Bus	Solar Spectrum
19	7	Chimpanzees
20	9	Sun	Laughing	Heartbeat
21	8	Wild Dog

However, some groups do not match up with their respective sounds exactly. The following images do not depict their sound:

4	Solar System	Surf
6	Continental Drift	Elephant
8	Mitosis	Riveter
11	X-Ray	Speech
12	Traffic	Thunder
15	Teacher	Ships
16	Anatomy	Herding Sheep
19	Solar Spectrum	Auto
20	Sun	Footsteps

It turns out that all these images actually come from the Voyager Golden Record's Scenes from Earth section. All of the images can be found here.

We take the canonical order of each image in the Scenes of Earth section. These numbers are from 1 to 116 so, as clued in the flavor text, we convert the numbers to their elemental symbol.

4	Solar System	#6	C
6	Continental Drift	#39	Y
8	Mitosis	#17	Cl
11	X-Ray	#99	Es
12	Traffic	#102	No
15	Teacher	#73	Ta
16	Anatomy	#22	Ti
19	Solar Spectrum	#8	O
20	Sun	#7	N

Reading down, we get CYClEsNoTaTiON, which clues that the permutation that was applied to scramble the order of the groups should be written in cycle notation.

1	17	Train
17	3	Mud Pots
3	20	Kiss	Mother and Child
20	9	Sun	Laughing	Heartbeat
9	1	Music of the Spheres
2	19	Plane	Rocket
19	7	Chimpanzees
7	12	Tame Dog
12	2	Volcano	Earthquake	Traffic
4	4	Wind	Solar System	Rain
5	11	Tool
11	10	Fire	X-Ray
10	5	Cricket	Frog
6	6	Birds	Hyena	Continental Drift
8	14	Tractor	Mitosis
14	21	EKG	Pulsar
21	8	Wild Dog
13	16	Horse and Cart
16	13	Anatomy	Sawing	Blacksmith
15	15	Morse Code	Teacher
18	18	Tractor	Bus	Solar Spectrum

Noticing that there is exactly one incorrect image in each cycle, we index the cycle length into the only piece of information we have not yet used, the name of the corresponding sound.

4	Solar System	Surf	length 1	S
6	Continental Drift	Elephant	length 1	E
8	Mitosis	Riveter	length 3	V
11	X-Ray	Speech	length 3	E
12	Traffic	Thunder	length 4	N
15	Teacher	Ships	length 1	S
16	Anatomy	Herding Sheep	length 2	E
19	Solar Spectrum	Auto	length 1	A
20	Sun	Footsteps	length 5	S

Reading down reveals the answer of SEVEN SEAS.