On the Subject of Gridlock

Even a traffic jam isn’t this stop and go.

  • A four by four grid is shown, with squares marked with colors and/or shapes.
  • The starting position is the square marked with a star.
  • Using the first table on the next page, find the direction indicated by the star and the color of that square.
  • The next position is the square 1 space in the direction indicated by the table lookup.
  • Press the NEXT button. This will change the information displayed on the module.
  • Continue finding positions using the following rules:
    • If the current square on the module has an arrow, move in the direction indicated by the arrow.
    • If the current square is colored, use the first table to look up the direction to move based on the symbol and color in the square, and press the NEXT button.
    • If the current square on the module is blank, find the table marked with the same color as the last colored square used, and move in the direction indicated based on the current position.
  • If at any point, a movement would result in landing on a previously occupied position, continue in the same direction until you land on an as-yet unused position.
  • The grid loops around, such that an upward movement from the top row will move to the bottom row of the same column, and likewise for left/right movement off the grid, or diagonal movement off the grid (for example, moving north-east from A1 leads to B4.)
  • At some point, an instruction will result in a gridlock, where all possible positions valid to move to have already been used.
  • The square that gave that movement is the solution. Hitting that square on the grid will disarm the module.
  • Hitting any other square in the grid will result in a strike and the module returning to its initial state.
  • The page number in the bottom-right of the module displays which set of symbols the module is currently showing. In some cases it may be necessary to loop back to the first page while solving the module.
Movement Blue Green Yellow Red
BLUE A B C D
1
2
3
4
GREEN A B C D
1
2
3
4
YELLOW A B C D
1
2
3
4
RED A B C D
1
2
3
4