MIT Mystery Hunt 2020/The Ferris of Them All

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

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 of

SIX-WHEELER.

The puzzle's icon - fittingly, it's a ferris wheel.

Puzzle Elements

• The Waterfall Effect - {{Spoilers|text=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.}}
• Masyu - Spin 1 is a Masyu puzzle, albeit on an abnormal grid shape.
• Slitherlink - Spin 5 is a Slitherlink puzzle, again on an abnormal grid shape.
• Number Placement (Logic Puzzle Type) - 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.
• Colour Placement (Logic Puzzle Type) - Similarly to 3 and 4, Spin 2 does not contain a specific logic puzzle, but instead uses logical principles to place colours based on a specific set of instructions.
• Circular Grid - Unlike some circular grids that may have a center space for use in multiple radiating sequences, this grid acts more like a ring, with nothing being placed in the central space.
• Measuring Distance (Arbitrary Units) - Segments along the gridlines are measured during the extraction section of the Final Spin.
• Alphanumeric Substitution Cipher - The final extraction relies on the conversion of distances measured between two points to letters, although these distances only ever reach 24 at maximum.