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⚠️  Note

This is an archived version of the 2026 Key Clues Challenge website. For information on the upcoming event, visit keyclueschallenge.uwaterloo.ca.

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Solution: Energy Equals MC Squared
Answer: BOXOFFICE

Based on "MC" in the title and the flavortext demanding on-campus presence, the puzzle directs solvers to the Mathematics & Computer building. Once inside MC, solvers may recognize the diagrams as abstract representations of various posters and structures within the building.

To help locate the posters/structures, the puzzle orders the diagrams based on floor number; from bottom floor to top.

With the exception of the 7th diagram, each diagram contains a single colored rectangle. The rectangle highlights some text on the poster/structure. As well, the rectangle's color corresponds with exactly one square on the 7th diagram. The 7th diagram represents the William Tutte "Squaring the Square" plaque. Each square on that plaque has an integer side length, which can be used as an index into the highlighted text to extract a letter. (Solvers can find the side lengths of the squares either by measuring the Squaring the Square diagram, or by finding the rectangle online.)

FLOORDESCRIPTIONHIGHLIGHTED TEXTCOLORCORRESPONDING "SQUARING THE SQUARE" SIDE LENGTHINDEXED LETTER
AnyClockSIMPLEXPink7X
1Set of doors beside a set of buttonsDO NOTRed4O
2V6.4 Draft Waterloo posterOPERATIONAL EXCELLENCEOrange18E
3Glass display outside MC ComfyNEW YORK STOCK EXCHANGEYellow15C
4Academic Advisors muralDINA DAWOUDGreen8O
5William Tutte displayBHANBHAGTA GURUNGCyan1B
5William Tutte "Squaring the Square" plaque
5Women of Mathematics posterHYPATIA OF ALEXANDRIATeal9F
5.1677...Number line stairwellVOLUME OF THE UNIT SPHERE IN ℝ6Blue14I
6Research posterPHYSICS INFORMED NEURAL NETWORKS FOR STABILITY ANALYSIS AND CONTROL WITH FORMAL GUARANTEESPurple10F

Reading the extracted letters in order of smallest square to largest gives the answer, BOX OFFICE, which is a loose description of MC.

Author’s Notes

Have you ever seen the trains lab meme window on the third floor of MC? It almost made it into this puzzle.