diff --git a/src/playfield.rs b/src/playfield.rs
index 08692cb..a70f122 100644
--- a/src/playfield.rs
+++ b/src/playfield.rs
@@ -55,6 +55,10 @@ impl Playfield {
     pub fn get_column(&self, index: usize) -> Vec<Field> {
         self.fields.iter().map(|row| row[index].clone()).collect()
     }
+    pub fn get_field(&self, row: usize, col: usize) -> &Field {
+        &self.fields[row][col]
+    }
+    pub fn convert_index(&self, index: usize) -> (usize, usize) {}
 }
 
 impl fmt::Display for Playfield {
@@ -117,6 +121,25 @@ mod tests {
             assert_eq!(column_3, expected_3);
         }
     }
+
+    mod convert_index {
+        use super::*;
+        #[test]
+        fn simple() {
+            let playfield = Playfield::new(&"1 2 3 0 0 0 0 0 0".to_string(), 3);
+            let (row_1, col_1) = playfield.convert_index(0);
+            assert_eq!(row_1, 0);
+            assert_eq!(col_1, 0);
+
+            let (row_2, col_2) = playfield.convert_index(4);
+            assert_eq!(row_2, 1);
+            assert_eq!(col_2, 1);
+
+            let (row_2, col_2) = playfield.convert_index(9);
+            assert_eq!(row_2, 2);
+            assert_eq!(col_2, 2);
+        }
+    }
     mod parse {
         use super::super::*;
 
diff --git a/src/sudoku_solver.rs b/src/sudoku_solver.rs
index 1019e58..94b6b0e 100644
--- a/src/sudoku_solver.rs
+++ b/src/sudoku_solver.rs
@@ -13,7 +13,9 @@ impl SudokuSolver {
             playfield: playfield.clone(),
         }
     }
-    pub fn solve(&self) -> Playfield {
+    pub fn solve(&mut self) -> Playfield {
+        self.populate_possible_values();
+
         return self.playfield.clone();
     }