Sticks And Stones

Solved! 💜 += 25;

They’re lunar stones.

You realize Steve’s stones are actually charged by moonlight; bringing them with you gives you enough light to navigate the tunnel. Using the LUNAR STONE ON RADICAL ROOTS, the seemingly insane route is actually not too difficult to navigate.

“Ah, so ya figured out how to get back to your side?”

You turn around to see that Steve has returned. Well, figures he’d only come around now.

“So… this is goodbye?” you ask.

“Beats me. You’re the one standing by the exit.”

You’re left without words again, and stand awkwardly as you fumble for a response. This isn’t quite how you’re used to saying goodbye.

Finally, you manage to ask, “so what was that deal about being assistant director?”

“Yeah, you got to be assistant director. What about it? Seemed you figured out everything just fine.” Steve thinks for a moment, and then grins. “Oh, you need like a work reference or something?”

“I…”

“Consider it done!” Steve claps his hands together. “I’ll have it mailed out later tonight.”

“Wait…”

Steve interrupts you before you can even finish gathering your thoughts. “Geez, you sure know how to drag on a goodbye! Take it easy. Things come and go, but you’ll figure it out.”

And with that, Steve turns around, makes a short farewell gesture, and fades into the darkness.

Click the image to continue.

Solution to Sticks And Stones

The metapuzzle requires the undordered set of the feeder answers to the previous puzzles, which we give below sorted first by length and then alphabetically.

GETSUMNULL
KAZAKHSTAN
BEACONRADIUS
SAYNOTOCOMBO
USACHROMAKEY
FILESPECIALFORMAT
TEAMSELECTIONEXAM

It’s also necessary to find the puzzle itself: it’s hidden in the same place that the hunt itself was, behind the world map (this time behind the MOSP world map).

Braille

The first step is to translate the Braille grid provided. Doing so provides the following message:


N	E	W	J	O	B
F	I	N	D
A		T	E	S	T
O	N	E	V	A	N
C	H	E	N	C	C
A		P	D	F
S	O	L	N
		T	E	X	T
U	S	A	J	M	O
P		S	I	X

This prompts the solver to navigate to the problem archive at evanchen.cc. One of the tests has been conspicuously labeled “featuring Steve” for no apparent reason, so the solver is prompted to open it. Doing so reminds the solver of the statement of USAJMO 2015/6:

Steve is piling $m\geq 1$ indistinguishable stones on the squares of an $n\times n$ grid. Each square can have an arbitrarily high pile of stones. After he finished piling his stones in some manner, he can then perform stone moves, defined as follows. Consider any four grid squares, which are corners of a rectangle, i.e. in positions $(i, k), (i, l), (j, k), (j, l)$ for some $1\leq i, j, k, l\leq n$, such that $i<j$ and $k<l$. A stone move consists of either removing one stone from each of $(i, k)$ and $(j, l)$ and moving them to $(i, l)$ and $(j, k)$ respectively, or removing one stone from each of $(i, l)$ and $(j, k)$ and moving them to $(i, k)$ and $(j, l)$ respectively.

Two ways of piling the stones are equivalent if they can be obtained from one another by a sequence of stone moves. How many different non-equivalent ways can Steve pile the stones on the grid?

The solution to this problem is based on looking at the “signature” of a stone configuration: the number of stones in any given row or given column. This suggests the blue numbers given are the signature.

Crossword

It remains to complete the crossword. To proceed further, one has to read the flavor text of the puzzle. Reading it out loud, one should notice something conspicuous: as is MOSP tradition, the letter S is repeated over and over (though not quite as much as in the survey). And indeed, one notices that each of the answers has the letter S exactly once. So this suggests the way to fill in the grid:

The letter S’s represent the stones, and should satisfy the blue numbers.
The answers should be placed in the grid with three horizontal and four vertical; moreover the occupied cells must be centrally symmetric.

It turns out there is a unique way to do this, depicted below.

	1	2	1	0	0	0	0	0	0	1	1	1
0			T
0			E								G
1	U	S	A	C	H	R	O	M	A	K	E	Y
0			M								T
2			S								S
0			E								U
0			L								M
0			E								N
0			C								U
0			T								L
0			I								L
0			O
0			N
0			E
0			X							F
1	B	E	A	C	O	N	R	A	D	I	U	S
0			M							L
0										E
1										S
0										P
0		K								E
0		A								C
0		Z								I
0		A								A
0		K								L
0		H								F
1		S								O
0		T								R
1	S	A	Y	N	O	T	O	C	O	M	B	O
0		N								A
0										T

Extraction

There is one step remaining: solvers need to overlay this completed grid back onto the Braille grid (since there was otherwise no reason why the Braille grid should be the same dimensions as the crossword; moreover some of the placement of empty cells in the Braille was fairly irregular).

Upon doing so, certain letters are highlighted, as shown below. The solver then should trace out the S and read the highlighted letters, as directed by the flavor text.


		.
		.								.
.	.	A	C	H	R	O	M	A	K	E	.
		M								T
		S								S
		E								U
		L								M
		E								N
		C								U
		T								L
		I								L
		O
		N
		E
		X							.
.	.	A	C	O	N	R	A	D	I	.	.
		.							L
									E
									S
									P
	K								E
	A								C
	Z								I
	A								A
	K								L
	H								F
	S								O
	T								R
.	A	Y	N	O	T	O	C	O	M	.	.
	.								.
									.

Reading this gives the answer: LUNAR STONE ON RADICAL ROOTS.

Author Notes

Since the puzzle hunt was named MOSP, I wanted the metapuzzle to be based around the letter S. I had the idea of using Steve’s stones, from USAMO 2015, as the mechanic, since it was a reference that this group might appreciate.

The original form of the puzzle was a bit simpler. The only given data was

A link to the Steve’s stones problem in the flavortext
The blue numbers
The indices of the extracted letters along the S-path (out of 66).

The problem with this was that test-solvers kept trying to use the numbers 1-66 much too early. (There was also not enough confirmation that a crossword was the right thing to do, which we fixed by providing the across/down hint.) To alleviate the other issue, we converted the “look at USAMO 2015/4” text into an additional Braille step, carefully using Nutrimatic to create a cluephrase that would unambiguously point to JMO 2015/6, while ensuring the pattern of highlighted letters in the giant S would extract to the desired final answer. This way people wouldn’t try to reuse the green cells until towards the end, since they start by getting an instruction out of it, that pointed them towards a specific thing to think about.

The title of the puzzle used to be “Escape from MOSP”, but was revised several times to clue the mechanic. “Sticks and Stones” conveniently clues both the S and the olympiad problem.

	1	2	1	0	0	0	0	0	0	1	1	1
0			T
0			E								G
1	U	S	A	C	H	R	O	M	A	K	E	Y
0			M								T
2			S								S
0			E								U
0			L								M
0			E								N
0			C								U
0			T								L
0			I								L
0			O
0			N
0			E
0			X							F
1	B	E	A	C	O	N	R	A	D	I	U	S
0			M							L
0										E
1										S
0										P
0		K								E
0		A								C
0		Z								I
0		A								A
0		K								L
0		H								F
1		S								O
0		T								R
1	S	A	Y	N	O	T	O	C	O	M	B	O
0		N								A
0										T


		.
		.								.
.	.	A	C	H	R	O	M	A	K	E	.
		M								T
		S								S
		E								U
		L								M
		E								N
		C								U
		T								L
		I								L
		O
		N
		E
		X							.
.	.	A	C	O	N	R	A	D	I	.	.
		.							L
									E
									S
									P
	K								E
	A								C
	Z								I
	A								A
	K								L
	H								F
	S								O
	T								R
.	A	Y	N	O	T	O	C	O	M	.	.
	.								.
									.

	1	2	1	0	0	0	0	0	0	1	1	1
0			T
0			E								G
1	U	S	A	C	H	R	O	M	A	K	E	Y
0			M								T
2			S								S
0			E								U
0			L								M
0			E								N
0			C								U
0			T								L
0			I								L
0			O
0			N
0			E
0			X							F
1	B	E	A	C	O	N	R	A	D	I	U	S
0			M							L
0										E
1										S
0										P
0		K								E
0		A								C
0		Z								I
0		A								A
0		K								L
0		H								F
1		S								O
0		T								R
1	S	A	Y	N	O	T	O	C	O	M	B	O
0		N								A
0										T


		.
		.								.
.	.	A	C	H	R	O	M	A	K	E	.
		M								T
		S								S
		E								U
		L								M
		E								N
		C								U
		T								L
		I								L
		O
		N
		E
		X							.
.	.	A	C	O	N	R	A	D	I	.	.
		.							L
									E
									S
									P
	K								E
	A								C
	Z								I
	A								A
	K								L
	H								F
	S								O
	T								R
.	A	Y	N	O	T	O	C	O	M	.	.
	.								.
									.

	1	2	1	0	0	0	0	0	0	1	1	1
0			T
0			E								G
1	U	S	A	C	H	R	O	M	A	K	E	Y
0			M								T
2			S								S
0			E								U
0			L								M
0			E								N
0			C								U
0			T								L
0			I								L
0			O
0			N
0			E
0			X							F
1	B	E	A	C	O	N	R	A	D	I	U	S
0			M							L
0										E
1										S
0										P
0		K								E
0		A								C
0		Z								I
0		A								A
0		K								L
0		H								F
1		S								O
0		T								R
1	S	A	Y	N	O	T	O	C	O	M	B	O
0		N								A
0										T


		.
		.								.
.	.	A	C	H	R	O	M	A	K	E	.
		M								T
		S								S
		E								U
		L								M
		E								N
		C								U
		T								L
		I								L
		O
		N
		E
		X							.
.	.	A	C	O	N	R	A	D	I	.	.
		.							L
									E
									S
									P
	K								E
	A								C
	Z								I
	A								A
	K								L
	H								F
	S								O
	T								R
.	A	Y	N	O	T	O	C	O	M	.	.
	.								.
									.