---
chars := chars char
  chars := chars char
    chars := chars char
      chars := chars char
        chars := 
        char := "CHAR"
          CHAR "a" (1, 1)
      char := "CHAR"
        CHAR "b" (1, 2)
    char := "CHAR"
      CHAR "c" (1, 3)
  char := "CHAR"
    CHAR "d" (1, 4)