The Ferris of Them All (MIT Mystery Hunt 2020)

The Ferris of Them All
MIT Mystery Hunt 2020
The Grand Castle
The puzzle's icon - fittingly, it's a ferris wheel.
Author(s)Mark Gottlieb, Todd Etter (graphic design)
AnswerClick to revealSIX WHEELER

The Ferris of Them All is a logic-based puzzle from the Grand Castle round of the 2020 MIT Mystery Hunt. It features a sequential series of circles divided up into rectangular regions, and uses elements of several different popular logic puzzle types.

Solve Path[edit | edit source]

The puzzle doesn't leave too much to investigation work, instead choosing to provide instructions for all of the sub-puzzles involved.


Solving each wheel is necessary to provide information required to solve the subsequent wheel, but at no point do any of the wheels aside from the last provide information pertaining to the final answer or its extraction method. As all of the logic puzzles are unique, the solve path for them is relatively straightforward. In addition, the final wheel also provides a key piece of information regarding extraction, namely the instruction to "count the number of straightaways that [the riders] ride." When doing so, a solver can order the resulting numbers by the rider's numbered label and apply the common alphanumeric substitution cipher, resulting in the final answer.}}

ANSWER: Click to revealSIX-WHEELER.

Puzzle Elements[edit | edit source]


Circular Grid - Fitting in with the ferris-wheel theme, all of the grids for these logic puzzles are circular. Unlike some circular grids that may have a center space for use in multiple radiating sequences, however, this grid acts more like a ring, with nothing being placed in the central space.

Explicit Instructions - Thankfully, the puzzle doesn't complicate things further by leaving out instructions on solving the puzzles. It even goes as far as explaining the puzzle types that are already well-established.

The Waterfall Effect - Each circular puzzle feeds into the next, such as providing givens or crucial markings, requiring solving of the previous wheel before being able to begin work on the next. While each of the individual "spins" may have multiple ways of approaching them (as is the case with many logic puzzles), this mechanic forces them to be solved in a linear order.

Masyu - Spin 1 is a Masyu puzzle, albeit on an abnormal grid shape. Otherwise, it functions just like any other Masyu.

Colour Placement (Logic Puzzle Type) - Spin 2 does not contain a specific pre-established logic puzzle, but instead uses logical principles to place colours (red, blue, and green) based on its instructions.

Number Placement (Logic Puzzle Type) - Similar to Spin 2, while there is no specific named type of logic puzzle at play here, Spins 3 and 4 function via the placement of numbers based on a set of instructions and deductions. Spin 3 has a bank of numbers to place, while Spin 4 requires an unknown mix of 0s, 1s, 2s, and 3s.

Slitherlink - Spin 5 is a Slitherlink puzzle, again on an abnormal grid shape, and again with not much in terms of gimmicks.

Measuring Distance (Arbitrary Units) - The final spin is where the puzzle strays from its logic-puzzle core. Instead, it requires solvers to rotate the path made in Spin 5 so that it passes over all of the stars and circles. Then, they can measure the distance between pairs that have the same number, although it's in arbitrary units since the distance going up the side of a cell is treated as the same as going across, despite a clear discrepancy between them.

Alphanumeric Substitution Cipher - Once the measurements are...well, measured, solvers can convert the numbers to letters (A1Z26-style) to get their final answer, keeping the order determined by the star/circle numbers.

Thematic Answer(?) - The final answer ends up being a perfect description of the puzzle as a whole, considering the six circular grids it takes place on.