Six coloured lines run across the sheet like a subway map. Ride a line outward from its terminus: each station teaches one idea and unlocks the next one on that line.
A double-ring station is an interchange: a concept shared by more than one line. Some stations need knowledge from a different line before they unlock.
Locked stations are grey and dashed. Tap one and it tells you exactly what to learn first, with a button that takes you there. Gold means learned: never red.
Drag to pan, pinch or scroll to zoom. Use PLAN A JOURNEY to draw the shortest legal route to any locked station.
This clears every learned station on The Lines. It can't be undone.