{
    "hints":  [
                  {
                      "text":  "Fold the figure along the given line.",
                      "level":  1
                  },
                  {
                      "text":  "Check that both halves match exactly.",
                      "level":  2
                  },
                  {
                      "text":  "The line splits the shape into identical halves, so it is a line of symmetry.",
                      "level":  3
                  }
              ]
}