diff --git a/src/repr.rs b/src/repr.rs
index bf12bed..96632b0 100644
--- a/src/repr.rs
+++ b/src/repr.rs
@@ -50,16 +50,19 @@ impl Board {
 
         for i_range in i_ranges {
             let mut chain_length: usize = 0;
-            for new_i in i_range {
+            for new_i in i_range.clone() {
                 match self.get(new_i, j) {
                     Some(piece) => {
                         if piece == &starting_color {
                             if chain_length > 0 {
-                                todo!("matching end")
+                                // fill all opposite colors with this color
+                                i_range.get(..chain_length).unwrap().iter().for_each(|i_o| {
+                                    self.place_and_prop_unchecked(*i_o, j, starting_color)
+                                });
                             }
                             break;
                         } else {
-                            todo!("add to the chain");
+                            chain_length += 1;
                         }
                     }
                     None => break,
@@ -68,10 +71,26 @@ impl Board {
         }
 
         for j_range in j_ranges {
-            for new_j in j_range {}
+            let mut chain_length: usize = 0;
+            for new_j in j_range.clone() {
+                match self.get(i, new_j) {
+                    Some(piece) => {
+                        if piece == &starting_color {
+                            if chain_length > 0 {
+                                // fill all opposite colors with this color
+                                j_range.get(..chain_length).unwrap().iter().for_each(|j_o| {
+                                    self.place_and_prop_unchecked(i, *j_o, starting_color)
+                                });
+                            }
+                            break;
+                        } else {
+                            chain_length += 1;
+                        }
+                    }
+                    None => break,
+                }
+            }
         }
-
-        todo!("propegation is not implemented");
     }
 
     fn place_and_prop_unchecked(&mut self, i: usize, j: usize, piece: Piece) {