tubechallenge.com

Are you in Zone 1?

NO, I am not in Zone 1 [7/20]

Are you at an interchange station?

YES, I am at an interchange station [8/20]

(Announcement: An interchange station shall hereby be defined as a station marked by a black and white blob on the "Tube, DLR, Trams and Train Travelcard zones Map". Announcement ends.)

Are you on a tube line?

YES, I'm on a tube line [9/20]

Is the interchange station you at served by other deep level Tube lines?

If I can rephrase that as "is your station served by more than one deep-level tube line": (that way it doesn't assume the trueness of the previous questions - hope I've got the gist of your question right...)

NO, not served by more than one deep-level tube line [10/20]

So, the state of play after 10 questions:

• NO, not South of (the southernmost branch of) the Central line
• NO, I am not North of the Northern limits of the Circle line
• NO, not south of the Thames
• NO, I am not at Dollis Hill
• YES, I am on a red, green or (any shade of) blue line
• NO, not west of the Charing Cross/Edgware branch of the Northern line
• NO, I am not in Zone 1
• YES, I am at an interchange station
• YES, I'm on a (deep-level) tube line
• NO, not served by more than one deep-level tube line

Is your line a shade of Blue?

NO, not on a line which is a shade of blue [11/20]

Are you on the Central Line?

YES, I am on the Central line [12/20]

Are you on the Hainhault(sic)loop?

NO, not on the Hainhault loop [13/20]

(...which I'll consider to be the all stations on the Central line north of Leytonstone and south of Buckhurst Hill)

Are you west of Zone 1?