Solution: Blockchain


Author: Dan Simon

Blockchain (logic part):

This part can be solved via noticing that certain rectangles have only one legal placement (given those placed before), usually via otherwise intersecting other rectangles too much. Rectangles have to have height × width = area, which restricts them to a small number of options which can be manually considered and mostly ruled out. It’s very useful to note that a rectangle can never intersect another clue, as explicitly stated in the rules; this creates certain forbidden cells. These forbidden cells, and edges, rule out a lot of options; for example, a size-6 rectangle with nothing around it has 24 options, but a single adjacent clue or adjacent edge of the grid brings that down to 12 options.

There's a lot of freedom in what order you do things in, but one possible solve path is this:

Crypto (cryptic clues part):

As the puzzle says, these are cryptic clues (though lengths and enumerations are not given, which is somewhat atypical). The answers and mechanisms are below.

Spot sent vial without any openings? PossiblePOTENTIALLetter removal_POT _ENT _IALPossible9
Southern United States city's weird toll tickerLITTLE ROCKAnagram<TOLLTICKER>Southern United States city10
Unusual state crop observerSPECTATORAnagram<STATECROP>Observer9
Start unstarted dessertTARTLetter removal_TARTDessert4
High wire, peculiar to the gripTIGHTROPEAnagram<TOTHEGRIP>High wire9
Ride around diverse, unbounded area next to waterwayRIVERSIDEContainer, letter removalR(_IVERS_)IDEArea next to waterway9
Celebrity's rodents returningSTARReversal>RATSCelebrity4
Jousts strangely, in this precise wayJUST SOAnagram<JUSTSO>In this precise way6
Possess only weekly newspapers at firstOWNFirst lettersO_ W_ N_Possess3
Gas found in Maine onlyNEONHidden word_NE ON_Gas4
Me — me — in confused urgent conspiracyINTRIGUEAnagram, charade, containerI + <URG(I)ENT>Conspiracy8
Guys and you announced list of mealsMENUCharade, homophoneMEN + U (sounds like YOU)List of meals4
Tango in messy, messy processSYSTEMAnagram, charade<MES(T)SY>)Process6
Arrived reckless, yet at first not wanting to be photographedCAMERASHYCharade, first letterCAME + RASH + Y_Not wanting to be photographed9
Putting it together:

The lengths of the cryptic clue answers match the sizes of the rectangles. In fact, following the chain, starting from the top-left rectangle, the rectangle lengths match the cryptic clue answer lengths in the given cryptic clue order. (The other end of che chain is also a rectangle of size 9, but there is only one rectangle of size 10 in the chain, and the second cryptic clue answer is length 10, so this quickly becomes unambiguous.)

This matching suggests that we want to write clue answers in rectangles (as does the flavortext, "Put crypto on the blockchain!"). Doing this in a top-to-bottom, left-to-right way within each rectangle, we notice that the overlapping letters at rectangle intersections match:


The fact that the overlapping letters match suggests that we should read them (starting from the top-left rectangle, as with the cryptic clues). This gives us LETTERSONNUMS, which we can reparse as LETTERS ON NUMS:


Finally, we take the letters on the given number-clues, and read them in top-to-bottom, left-to-right order within the grid (not in chain order; we've already used chain order enough):


This gives us ANSWER CRASHING, meaning the answer is CRASHING, which answers the flavortext's question "What could go wrong?" with putting crypto on the blockchain.

Author’s Notes

Up until I wrote this author's note, I thought putting cryptic clue answers in a grid that is also a logic puzzle was an idea as old as dirt, but I'm actually having trouble finding a third puzzle like this. Anyway, I didn't really think of this as an especially creative puzzle idea and was mostly going for theming. I hope that "blockchain" felt like it fit the logic puzzle's rules, that "crypto" felt like it fit the cryptic clues, that teams understood after they solved that "What could go wrong?" was a reference to the answer "crashing" (perhaps aided by bitcoin's long-time lows during the hunt), and that the whole thing generally felt thematic. The other thing I was trying to do (besides make a cryptic/logic puzzle) was make a "crypto" puzzle that actually had nothing to do with cryptocurrency but still felt themed.

The logic puzzle rules are somewhat long, but all the special conditions there feel right given the blockchain theming (in my opinion). Hopefully the example helped teams understand the rules.