Solution to Runaround Training

Back to Puzzle


by Jakob Weisblat

Despite its appearance, this puzzle is not a runaround on MIT campus.

The first thing we have to realize, either by reading these descriptions and thinking that the descriptions of “hallways” don't seem like MIT corridors, or by looking at “colorful” in the text of the puzzle, or by looking at different interpretations until the data makes sense, is that this puzzle is about subway trains. We start at Kendall/MIT and follow the instructions, interpreting things seen around MIT as similar things seen around the real world.

Clue Explanation Station Extraction Phrase Letter
Start somewhere at MIT. Head east, through a hallway with a nice view. Turn right at the second opportunity, and head six doors down the hallway. You should have just passed the running track out the window to your left. Take the third letter of the first name on the nearest door. Start at Kendall/MIT. Head east on the Red Line, crossing the Longfellow Bridge with a nice view. Transfer at Downtown Crossing onto the Orange Line. Take the Orange Line south to Roxbury Crossing. The Reggie Lewis State Track Athletic Center is to the left. Take the letter X from Roxbury. Roxbury Crossing Roxbury Crossing X
Continue down the hallway, stopping at a door with a geometric shape on it. Write down the fourth letter of the name on that door. Continue on to Jackson Square. Take the letter K from Jackson Square. Jackson Square Jackson Square K
Turn around and head in the opposite direction until you reach a part of the hallway where you can't see the sky for a while. Just before there, there is a facility to the right named for a person whose first name is often abbreviated to an English word. Write down the first letter of his last name. Head north on the Orange Line (which, for a while, runs underground but uncovered) until you reach Mass Ave Station, where it is covered again. Just before the track enters the tunnel, it passes William E. Carter School to the right. William is abbreviated to Will. Write down the C of Carter. Mass Ave William E. Carter C
Continue until you reach a big intersection with another hallway. Turn left and then immediately right. There's a large brutalist building up ahead with a three-word name. Write down the last letter of the first name of its lead architect/designer. Continue north to Downtown Crossing. Transfer onto the Red Line and then at Park Street transfer to the Green Line. Up ahead is Boston City Hall, and the lead architect/designer is Gerhard Kallmann. Take the D of Gerhard. Government Center Gerhard Kallmann D
Pretty soon, you should pass some science demonstrations on your left. Continue in the same direction (even if it seems impossible) until you see a building that opened in 1976 and was renovated into a Course 7 lab in 1992. Write down the first letter of the lab's name. Pass the Museum of Science on your left. Continue northwest... past the end of the Green Line???

On the fifth instruction, we reach a hiccup; we don't know how to continue beyond the end of the Green Line; even the puzzle acknowledges that it seems impossible. However, if we've been careful so far, we've now extracted the letters XKCD. Searching for “xkcd subways” yields a relevant xkcd comic that will help us solve the rest of the puzzle. In this map, the Green Line continues on to Montreal rather than ending at Lechmere. With this insight, we can solve the rest of the clues:

Clue Explanation City Station Extraction Phrase Letter Line Color
Pretty soon, you should pass some science demonstrations on your left. Continue in the same direction (even if it seems impossible) until you see a building that opened in 1976 and was renovated into a Course 7 lab in 1992. Write down the first letter of the lab's name. Pass the Museum of Science on your left. Continue northwest into Montreal, where you're on the Green Line heading southwest. On the right, shortly before Pie IX Station, is the Montreal Biodome, which was built for the 1976 Olympics and now houses replicas of different North American ecosystems. Take the B of Biodome. Montreal Pie IX Biodome B Green
Continue in the same direction as you've been going, until you reach a place where many hallways intersect. Turn in the direction whose hallway is the shortest, and go halfway down the hallway. You just passed under a really big pipe. Write down the last letter of the first word of the two-word place the pipe leads to. Continue southwest on the Green Line to Berri-UQAM, and then transfer to the Yellow Line. Ride this train for one stop, to Jean-Drapeau Station. You pass under the Saint Lawrence River, which drains to the Atlantic Ocean. Take the C of Atlantic. Montreal Olympic Park Atlantic Ocean C Yellow
Go back to the intersection from the last paragraph, and this time go in the direction (other than the hallway you were in before) that goes the farthest before it ends. Continue in this new direction until you reach the second intersection. It may not look like it as you approach, but you can turn left here. Turn left and continue walking forward until the color of the walls changes. Veer right, and continue forward until you reach the second intersection with another hallway. There should be a Course 21 building across the street from where you are now. Turn right. Continue until you reach a door with a name whose second, third and fourth letters are the same. Write down that letter immediately following that letter in the alphabet. Head back to Berri-UQAM on the Yellow Line, then transfer to the Orange Line toward Snowdon, where it intersects the Blue Line. Transfer onto the Blue Line, ending up in Toronto. Take Line 3 (blue) to its end, and then transfer to Line 2 (green). Continue to St. George Station, which is across the street from the Jackman Humanities Institute. Transfer to Line 1 (yellow) and ride to the end of the line and onward to Vancouver. Take the Millenium Line (yellow) to VCC-Clark, and write down the letter D (one after C). Vancouver VCC-Clark VCC-Clark D Yellow
Turn around, and retrace your steps up until you reach an intersection that lets you turn southwest. Head that direction until you find a place where many hallways come together. Do your best to ignore the other hallways and follow this one. Eventually, you'll reach a place where it looks like the walls have been repainted recently. Don't let that trip you up; continue along this hallway (even if it takes a while) until you see an institute parking lot (#7) out the window to your right. The triangular building across the parking lot from here has a three word name; write down the letter that occurs most often in its name overall. Turn around and leave Vancouver, heading southwest toward San Francisco. Take the Antioch–SFO/Millbrae line all the way through San Francisco and continue on to Los Angeles. Take the G line (orange now, but yellow on the xkcd map) to Pierce College, and note parking lot #7 to the south. Across the way is Pierce College Library, a triangular building whose most common letter is E. LA Pierce College Pierce College Library E Yellow
Now return to the place where lots of hallways come together, and stay in this hallway the whole time until you see a door with a prime room number. At that point, turn around, and veer left at the first opportunity. Continue forward until you see a preponderance of parking lots to your right. At the center of them are two facilities; write down the sixth letter of the namesake of the nearer facility. Head back to downtown San Fransisco, where a lot of lines run together for a few stops. Continue along the Antioch–SFO/Millbrae line (yellow) to 19th St/Oakland, and then transfer to a southbound Berryessa/North San José–Richmond (orange, formerly Fremont-Richmond) line train. At Coliseum Station there is a preponderence of parking lots to the right, and the nearer one is the RingCentral Coliseum. Take the E of RingCentral. SF Airport/Coliseum RingCentral E Orange
Continue along this hallway for a long time, following when the hallway makes an abrupt right. Continue aways until you pass a Course 16 lab on the right. Shortly afterward, you'll see a facility on the left named for a Nobel-winning physicist. Write down the first letter of the physicist's last name. Continue southeast toward Fremont, eventually entering Los Angeles. Take the L line from one end to the other, ending up in Chicago. Shortly after Midway Airport, there are a high school and a park on the left, both named for Marie Curie. Take the C of Curie. Chicago Pulaski Marie Curie C Orange
Continue forward until you reach a rotunda. Take the hallway leading south out of there that immediately veers right. Continue until you see the admissions office on your left. On the other side of the hallway, facing the admissions office, is something sharing its name with the last name of a former president. Write down the fourth letter of that last name. Keep going to the Chicago Loop. Take the Blue Line to Racine, where the UIC admissions office is to the left. On the other side is Van Buren Lofts. Take the B from Van Buren. Chicago Racine Van Buren B Blue
Go back to the rotunda, this time exiting through a hallway that leads west. Continue, following the hallway as it turns, until you pass the university medical center on your left. Right in front of it is an establishment that sells food. Write down the first letter of the name of that establishment. Head back to the Loop, and take the Pink Line out of it this time. Shortly before Polk Station is the Rush University Medical Center. In front of it is an Au Bon Pain. Take the A from Au Bon Pain. Chicago Polk Au Bon Pain A Purple
Go back to the rotunda one more time, head downstairs, and go north. You'll pass a door whose name really ought to be more specific than it is. Ten doors later, write down the first letter of the name on that door. Head back to the Loop. Instead of transferring to another train that runs on the Loop, head underground and transfer to a northbound Red Line train. Pass the amusingly named Chicago Station, and continue 10 stops further to Berwyn. Take the B from Berwyn. Chicago Berwyn Berwyn B Red
Turn around, and go until you reach a door with a square number. To the left out the window, across the street, you see a popular place to go for food. Write down the first letter of the middle name of the second of the two names in the name of the architectural firm that designed it. Take the Red Line south until it turns east and enters Cleveland. The first square-numbered stop you reach is West 25th–Ohio City Station. Across the street is the West Side Market, where the author fondly remembers going on field trips in elementary school and middle school. Their building was built by Hubbell and Benes. Take the D from W. Dominick Benes. Cleveland 25th St-Ohio City Hubbell and Benes D Red
Shortly ahead, this hallway joins another. When they diverge, take the right branch, and then when the hallway splits again, take the right branch again. Continue along the current hallway, quite a ways, until you see two very famous historical landmarks out the window on the left. One of them should remind you of telephones and music. Take the last two digits of the year the other one opened, and subtract 1. Continue forward until you find a door with that number on it. Just before this door, out the window to the left, there is a business whose first word begins with D and ends with E. Write down the first letter of its second word. Continue eastward to Tower City, where the Red, Green and Blue lines all run together for a few stops. Take the Blue Line toward Van Aken, and continue into Philadelphia. Take the Market–Frankford Line (blue) downtown until you see Independence Hall and the Liberty Bell out the window near 5th Street. The Liberty Bell reminds us of music and the Bell telephone companies, so we take the year Independence Hall opened, 1753, and we go to 52nd St. Just before 52nd is a business called Double Connect. Take the C from Double Connect. Philadelphia 52nd St Double Connect C Blue
Turn around and continue a short distance until you reach a place where this hallway meets another. Turn right and continue down that relatively windy hallway until it reaches an intersection where four wide hallways meet at right angles. Turn left here. Walk very fast until you find yourself in a place whose name begins with state. Continue two doors down, and then look out the window to the right. You can see a green space whose name fits the enumeration 5 5 7 5 6. Write down the first letter of the last word in its name. Head back to the point at which the trolley line (green) diverges from the Market–Frankford Line (blue), and take the trolley south, passing through Greenbelt and onto the Green Line in Baltimore. Continue into Washington, D.C., and transfer to an eastbound Blue Line train at L'Enfant Plaza Station. Take the Robert Moses high-speed line to Staten Island, and continue to just past Richmond Valley Station. Note North Mount Loretto State Forest out the window to the right, and take the F from Forest. NYC (Staten Island) Richmond Valley North Mount Loretto State Forest F Blue
Turn around and retrace your steps, walking very fast where necessary. Just before you reach the big intersection where four wide hallways meet, look at the display on the right put on by Course 16. One of the most impressive parts of the display belonged to a guy whose name fits the enumeration (7 9). Write down the second-to-last letter of his last name. Take the Staten Island Railway west, once again using the Robert Moses high-speed line to return to Washington. Just before L'Enfant Plaza, get off the train and visit the National Air and Space Museum. Charles Lindbergh's Spirit of St. Louis, in which he flew from New York to Paris, resides here. Take the G from Lindbergh. Washington Federal Center SW Charles Lindbergh G Blue
Continue into the intersection and turn left twice. Continue until you reach a door with three consonants and four vowels on it. Write down the vowel that occurs most on the door. Continue to L'Enfant Plaza Station and transfer to a southbound Green Line train. Take this train to Miami, and stop at Hialeah Station. Write down an A from Hialeah. Miami Hialeah Hialeah A Green
Go on, heading generally southeast then southwest through the hallway, until you reach a place named for an emperor. Turn left, and continue until you can see twenty red-roofed buildings out the window to the right. The street between you and those buildings is named for a former president. Write down the first letter of his first name. Continue southward, toward Monterrey. Take Line 2 (green) to Cuauhtémoc, and transfer there to an eastbound Line 1 (orange) train. South of Exposición Station is a preponderance of red-roofed buildings, and the road in between you and them is named for Benito Juárez, former president of Mexico. Take the B from Benito. Monterrey Exposición Benito Juárez B Orange
Turn around, and continue straight ahead until you see another Course 16 lab - the most popular one on campus. Write down the last letter of its first namesake. Take a westbound Line 1 (orange) train to the end of the line. Stop at ATL, the busiest airport in North America. Take the D from Hartsfield-Jackson. Atlanta ATL Hartsfield-Jackson D Orange
Continue in the same direction. After a while, you'll pass a display put on by Course 21A and another from Course 7 to your left. At the next intersection, there are two hallways that meet this one. After you turn down the correct one, walk two doors down and you should see an exhibition put on by course 21H on the left. Continue forward, stopping one door short of the door leading to the most popular room on campus. Look out the window to the left. There's a building that sounds like it ought to contain a number of trees. Write down the first letter of the number in its name. The line you're on curves south to become Line 7 (orange) in Mexico City. Pass the Museo Nacional de Antropología and the Zoológico de Chapultepec, and then transfer at Tacubaya to Line 1 (purple). Passing the Museo de Arte Moderno on the left, stopping at Zaragoza, one station before Pantitlán, the busiest station in North America. On the left is Módulo INE Cuatro Árboles. Take the C from Cuatro. Mexico City Zaragoza Cuatro Arboles C Purple
Continue forward to the intersection. Head in a direction such that 2 doors down is a Course 16 lab. This lab is named for someone you encountered earlier in the puzzle. Write down the third letter of that person's last name. Continue to Pantitlán and transfer to a Line 5 (yellow) train headed northwest. Pass MEX, which is named for Benito Juárez. Take the A from Juárez. Mexico City Terminal Aérea Benito Juárez A Yellow
Continue forward to the fourth intersection. The intersection belongs to Course 10. Turn right at the intersection. Continue walking, travelling however necessary to keep going, heading straight forward and staying in the same hallway whenever you have an opportunity to turn. Do not stop until you reach a door whose number is a multiple of 23 (but not 23 itself). Two doors down, out the window to the left, look at a body of water with three words in its name. Write down the first letter of the third word. Continue northwest to Petróleo (which belongs to Course 10) and then head East on Line 6 (red). Continue through the Chicxulub tunnel to Santo Domingo, then through the Mona tunnel to San Juan, then transfer to a submarine to Manhattan. Transfer a Bronx-bound 1 train (red), finally stopping at 207 St. Just ahead, separating Manhattan from the Bronx, is Sputyen Duyvil Creek. Take the C from Creek. NYC 207th St Sputyen Duyvil Creek C Red
Turn around and go back until you reach an intersection (it shouldn't be nearly as long a walk as the previous step). Turn sharply right at the intersection, and continue until you reach another door whose number is a multiple of 23. Look around for a street that has two different names. Write down the second-to-last letter of the first word of the longer name. Head back to 168 St Station, and transfer to an Inwood-207th Street bound A train (blue). Head back to Inwood, stopping at the end of the line, Inwood–207th Street Station. The station is on Broadway, also known as Juan Rodriguez Way. Take the A from Juan. NYC Inwood-207th St Juan Rodriguez A Blue
Turn around again, and walk down this hallway until you see a large pipe overhead just ahead. Write down the first letter of the first word written on the pipe. Take a Brooklyn-bound A train to Fulton Street. The East River passes over the tracks just ahead. Take the E from East. NYC Fulton St East River E Blue
Turn around once more, and head five or so doors down the hallway. It gets complicated here, but you need to turn left such that the color of the walls don't change and there's a different pipe crossing the hallway overhead. This time, after passing under the pipe, write down the third letter of the first word on it. Switch to an Inwood-207th St bound train once again, but this time get out at West 4th St Station and walk to the Christopher St PATH station, boarding a New Jersey-bound Hoboken-33rd St (blue) train. Cross under the Hudson River to Hoboken Station, then write down the D from Hudson. NYC (PATH) Hoboken Hudson River D Blue
Turn around, one last time, and where this hallway and another one diverge, take the other one instead. You'll see that the big pipe from the last step goes overhead in this hallway too. Soon enough, you'll reach an intersection with the hallway you walked through in your very very long walk from a few steps ago. Turn left here, and continue until you reach the door to the most popular room in this part of campus. Switch to another hallway here, and continue two doors down until you see a well-known Course 21M facility on your right. Write down the first letter of the middle name of its architect. Board a WTC-Hoboken (green) PATH train at Hoboken, passing under the Hudson River. At WTC/Fulton St, transfer to a Bronx-bound 1 train (red). At Times Sq-42nd St, the busiest station in the NYC subway system, transfer to a Queens-bound R train (yellow). Two stops ahead, at 7th Avenue-57th St, we're right outside of Carnegie Hall, designed by William Burnet Tuthill. Take the B from Burnet. NYC Carnegie Hall William Burnet Tuthill B Yellow
Just ahead, you can see a park out the window. It was designed by two landscape architects; write down the first letter of the first name of the one whose middle name is an English word. Central Park is ahead. It was designed by Frederick Law Olmsted and Calvert Vaux. Take the F from Frederick. NYC Carnegie Hall Frederick Law Olmsted F Yellow
Continue until this hallway turns right. It may look like there's two places for this to happen, but there's really only one. Continue until you reach a door bearing the name of a former president, and turn left. Down the hall, you'll see athletics facilities on your left and right. The one on the right is named for a woman born in 1943. Take the first letter of her first name. As of the time of publication of the xkcd map, the Second Avenue subway (Q) did not yet exist, so the only place to turn right is where the N, R, and W lines turn right into Queens. Take a Queens-bound R train to Jackson Hts/Roosevelt Ave, and transfer to a Flushing-Main St bound 7 (purple) train. A few stops ahead, at Mets/Willets Point, Citi Field is on the left and the Billie Jean King Tennis Center (of which Arthur Ashe stadium is a part - Arthur Ashe was born in 1943 but is a man) on the right. Take the B from Billie. NYC Mets Billie Jean King B Purple
Turn around, and head back, almost to the end of the hall, to an intersection with one other hallway. Turn right. Where it splits in three, take the left fork. Continue along this hallway, following it as it turns here and there, until you see a large Harvard University facility on your left out the window in the distance. Write down the first letter of either of the two words in its name. Take the 7, nearly to Times Sq-42nd St (the end on the xkcd map, though the 7 has since been extended), and transfer to a Bronx-bound D train. Take the D train to Boston. Stop at Forest Hills Station on the Orange Line, and note the Arnold Arboretum, a very large Harvard University facility, to the left. Take the A from Arnold or Arboretum. Boston Forest Hills Arnold Arboretum A Orange
Continue forward until your next opportunity to turn left. Head back home. Your colorful journey has taken you through all 18 areas of campus! Write down the 3rd letter of the first word on the last door you pass by on your way home. Take the Orange Line north to Downtown Crossing, and transfer to a Red Line train heading toward Alewife. Head back to Kendall/MIT. The last stop before there is Charles/MGH. Take the A from Charles. Boston Charles/MGH Charles/MGH A Red

Here is a glossary of the various terms used to refer to the world around as though they are MIT surroundings:

Term Interpretation
hallway subway line
door station
pipe river
popular room busy station
course 16 lab airport
the way things “seem” or “look” how things are in reality or on the current subway map for a city
the way things are the way things are on the xkcd map

Once we've completed our colorful journey through all 18 metro systems in North America (or the 18 that the xkcd comic knows about, anyway), we turn to extract an answer. Sadly, BCDEECBABDCFGABDCACAEDBFBAA is not a particularly good cluephrase. However, the colored blanks at the bottom help us find an insight — we need to extract from each color of line separately.

Each color extracts a contiguous set of letters starting with A; for example, blue extracts A through G. This suggests that we draw lines on the xkcd comic between the stations we visited of each color, in alphabet order.

Show red
Show orange
Show yellow
Show green
Show blue
Show purple
Hide path

This yields SW 9157, which, fittingly, is a color of paint: Sherwin-Williams 9157, or AUTUMN ORCHID, which fits into the second set of blanks at the bottom and is the answer to the puzzle.