On the Subject of 16 Coins

1000011010000111...

There will be 16 coins arranged in a 4x4 square: "H" is heads, "T" is tails. Follow the steps to determine the target coin, then click it.

  • Count the number of heads in the even columns (marked with an X below). If the number of heads is odd, the target coin is in an even column. Otherwise, it is in the other columns.
    x x
    x x
    x x
    x x
  • Count the number of heads in the right half (marked with an X below). If the number of heads is odd, the target coin is in the right half. Otherwise, it is in the other half.
    xx
    xx
    xx
    xx
  • Count the number of heads in the even rows (marked with an X below). If the number of heads is odd, the target coin is in an even row. Otherwise, it is in the other rows.
    o
    xxxx
    o
    xxxx
  • Count the number of heads in the bottom half (marked with an X below). If the number of heads is odd, the target coin is in the bottom half. Otherwise, it is in the other half.
    o
    o
    xxxx
    xxxx