Simplify the boundary logic a little

1 files changed, 90 insertions, 385 deletions

diff --git a/src/client/boundaries.rs b/src/client/boundaries.rs
index 28e01a11..ad444c93 100644
--- a/src/client/boundaries.rs
+++ b/src/client/boundaries.rs
@@ -69,620 +69,325 @@ fn combine_symbols(
     current_symbol: BoundarySymbol,
     next_symbol: BoundarySymbol,
 ) -> Option<BoundarySymbol> {
+    use boundary_type::*;
     let invisible = current_symbol.invisible || next_symbol.invisible;
-    let color = match (current_symbol.color.is_some(), next_symbol.color.is_some()) {
-        (true, _) => current_symbol.color,
-        _ => next_symbol.color,
-    };
-    let current_symbol = current_symbol.boundary_type;
-    let next_symbol = next_symbol.boundary_type;
-    match (current_symbol, next_symbol) {
-        (boundary_type::TOP_RIGHT, boundary_type::TOP_RIGHT) => {
-            // (┐, ┐) => Some(┐)
-            let boundary_type = boundary_type::TOP_RIGHT;
+    let color = current_symbol.color.or(next_symbol.color);
+    match (current_symbol.boundary_type, next_symbol.boundary_type) {
+        (CROSS, _) | (_, CROSS) => {
+            // (┼, *) or (*, ┼) => Some(┼)
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_RIGHT, boundary_type::VERTICAL) => {
-            // (┐, │) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
+        (TOP_RIGHT, TOP_RIGHT) => {
+            // (┐, ┐) => Some(┐)
+            let boundary_type = TOP_RIGHT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_RIGHT, boundary_type::HORIZONTAL) => {
-            // (┐, ─) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
+        (TOP_RIGHT, VERTICAL) | (TOP_RIGHT, BOTTOM_RIGHT) | (TOP_RIGHT, VERTICAL_LEFT) => {
+            // (┐, │) => Some(┤)
+            // (┐, ┘) => Some(┤)
+            // (─, ┤) => Some(┤)
+            let boundary_type = VERTICAL_LEFT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_RIGHT, boundary_type::TOP_LEFT) => {
+        (TOP_RIGHT, HORIZONTAL) | (TOP_RIGHT, TOP_LEFT) | (TOP_RIGHT, HORIZONTAL_DOWN) => {
+            // (┐, ─) => Some(┬)
             // (┐, ┌) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_RIGHT, boundary_type::BOTTOM_RIGHT) => {
-            // (┐, ┘) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
+            // (┐, ┬) => Some(┬)
+            let boundary_type = HORIZONTAL_DOWN;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_RIGHT, boundary_type::BOTTOM_LEFT) => {
+        (TOP_RIGHT, BOTTOM_LEFT) | (TOP_RIGHT, VERTICAL_RIGHT) | (TOP_RIGHT, HORIZONTAL_UP) => {
             // (┐, └) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_RIGHT, boundary_type::VERTICAL_LEFT) => {
-            // (┐, ┤) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_RIGHT, boundary_type::VERTICAL_RIGHT) => {
             // (┐, ├) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_RIGHT, boundary_type::HORIZONTAL_DOWN) => {
-            // (┐, ┬) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_RIGHT, boundary_type::HORIZONTAL_UP) => {
             // (┐, ┴) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_RIGHT, boundary_type::CROSS) => {
-            // (┐, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL, boundary_type::HORIZONTAL) => {
+        (HORIZONTAL, HORIZONTAL) => {
             // (─, ─) => Some(─)
-            let boundary_type = boundary_type::HORIZONTAL;
+            let boundary_type = HORIZONTAL;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL, boundary_type::VERTICAL) => {
+        (HORIZONTAL, VERTICAL) | (HORIZONTAL, VERTICAL_LEFT) | (HORIZONTAL, VERTICAL_RIGHT) => {
             // (─, │) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL, boundary_type::TOP_LEFT) => {
-            // (─, ┌) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL, boundary_type::BOTTOM_RIGHT) => {
-            // (─, ┘) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL, boundary_type::BOTTOM_LEFT) => {
-            // (─, └) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL, boundary_type::VERTICAL_LEFT) => {
             // (─, ┤) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL, boundary_type::VERTICAL_RIGHT) => {
             // (─, ├) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL, boundary_type::HORIZONTAL_DOWN) => {
+        (HORIZONTAL, TOP_LEFT) | (HORIZONTAL, HORIZONTAL_DOWN) => {
+            // (─, ┌) => Some(┬)
             // (─, ┬) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
+            let boundary_type = HORIZONTAL_DOWN;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL, boundary_type::HORIZONTAL_UP) => {
+        (HORIZONTAL, BOTTOM_RIGHT) | (HORIZONTAL, BOTTOM_LEFT) | (HORIZONTAL, HORIZONTAL_UP) => {
+            // (─, ┘) => Some(┴)
+            // (─, └) => Some(┴)
             // (─, ┴) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
+            let boundary_type = HORIZONTAL_UP;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL, boundary_type::CROSS) => {
-            // (─, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL, boundary_type::VERTICAL) => {
+        (VERTICAL, VERTICAL) => {
             // (│, │) => Some(│)
-            let boundary_type = boundary_type::VERTICAL;
+            let boundary_type = VERTICAL;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL, boundary_type::TOP_LEFT) => {
+        (VERTICAL, TOP_LEFT) | (VERTICAL, BOTTOM_LEFT) | (VERTICAL, VERTICAL_RIGHT) => {
             // (│, ┌) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL, boundary_type::BOTTOM_RIGHT) => {
-            // (│, ┘) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL, boundary_type::BOTTOM_LEFT) => {
             // (│, └) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
+            // (│, ├) => Some(├)
+            let boundary_type = VERTICAL_RIGHT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL, boundary_type::VERTICAL_LEFT) => {
+        (VERTICAL, BOTTOM_RIGHT) | (VERTICAL, VERTICAL_LEFT) => {
+            // (│, ┘) => Some(┤)
             // (│, ┤) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
+            let boundary_type = VERTICAL_LEFT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL, boundary_type::VERTICAL_RIGHT) => {
-            // (│, ├) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL, boundary_type::HORIZONTAL_DOWN) => {
+        (VERTICAL, HORIZONTAL_DOWN) | (VERTICAL, HORIZONTAL_UP) => {
             // (│, ┬) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL, boundary_type::HORIZONTAL_UP) => {
             // (│, ┴) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL, boundary_type::CROSS) => {
-            // (│, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_LEFT, boundary_type::TOP_LEFT) => {
+        (TOP_LEFT, TOP_LEFT) => {
             // (┌, ┌) => Some(┌)
-            let boundary_type = boundary_type::TOP_LEFT;
+            let boundary_type = TOP_LEFT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_LEFT, boundary_type::BOTTOM_RIGHT) => {
+        (TOP_LEFT, BOTTOM_RIGHT) | (TOP_LEFT, VERTICAL_LEFT) | (TOP_LEFT, HORIZONTAL_UP) => {
             // (┌, ┘) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_LEFT, boundary_type::BOTTOM_LEFT) => {
-            // (┌, └) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_LEFT, boundary_type::VERTICAL_LEFT) => {
             // (┌, ┤) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            // (┌, ┴) => Some(┼)
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_LEFT, boundary_type::VERTICAL_RIGHT) => {
+        (TOP_LEFT, BOTTOM_LEFT) | (TOP_LEFT, VERTICAL_RIGHT) => {
+            // (┌, └) => Some(├)
             // (┌, ├) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
+            let boundary_type = VERTICAL_RIGHT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_LEFT, boundary_type::HORIZONTAL_DOWN) => {
+        (TOP_LEFT, HORIZONTAL_DOWN) => {
             // (┌, ┬) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
+            let boundary_type = HORIZONTAL_DOWN;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::TOP_LEFT, boundary_type::HORIZONTAL_UP) => {
-            // (┌, ┴) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::TOP_LEFT, boundary_type::CROSS) => {
-            // (┌, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::BOTTOM_RIGHT) => {
+        (BOTTOM_RIGHT, BOTTOM_RIGHT) => {
             // (┘, ┘) => Some(┘)
-            let boundary_type = boundary_type::BOTTOM_RIGHT;
+            let boundary_type = BOTTOM_RIGHT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::BOTTOM_LEFT) => {
+        (BOTTOM_RIGHT, BOTTOM_LEFT) | (BOTTOM_RIGHT, HORIZONTAL_UP) => {
             // (┘, └) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
+            // (┘, ┴) => Some(┴)
+            let boundary_type = HORIZONTAL_UP;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::VERTICAL_LEFT) => {
+        (BOTTOM_RIGHT, VERTICAL_LEFT) => {
             // (┘, ┤) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
+            let boundary_type = VERTICAL_LEFT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::VERTICAL_RIGHT) => {
+        (BOTTOM_RIGHT, VERTICAL_RIGHT) | (BOTTOM_RIGHT, HORIZONTAL_DOWN) => {
             // (┘, ├) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::HORIZONTAL_DOWN) => {
             // (┘, ┬) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::HORIZONTAL_UP) => {
-            // (┘, ┴) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::BOTTOM_RIGHT, boundary_type::CROSS) => {
-            // (┘, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::BOTTOM_LEFT, boundary_type::BOTTOM_LEFT) => {
+        (BOTTOM_LEFT, BOTTOM_LEFT) => {
             // (└, └) => Some(└)
-            let boundary_type = boundary_type::BOTTOM_LEFT;
+            let boundary_type = BOTTOM_LEFT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_LEFT, boundary_type::VERTICAL_LEFT) => {
+        (BOTTOM_LEFT, VERTICAL_LEFT) | (BOTTOM_LEFT, HORIZONTAL_DOWN) => {
             // (└, ┤) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            // (└, ┬) => Some(┼)
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_LEFT, boundary_type::VERTICAL_RIGHT) => {
+        (BOTTOM_LEFT, VERTICAL_RIGHT) => {
             // (└, ├) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::BOTTOM_LEFT, boundary_type::HORIZONTAL_DOWN) => {
-            // (└, ┬) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = VERTICAL_RIGHT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::BOTTOM_LEFT, boundary_type::HORIZONTAL_UP) => {
+        (BOTTOM_LEFT, HORIZONTAL_UP) => {
             // (└, ┴) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::BOTTOM_LEFT, boundary_type::CROSS) => {
-            // (└, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = HORIZONTAL_UP;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL_LEFT, boundary_type::VERTICAL_LEFT) => {
+        (VERTICAL_LEFT, VERTICAL_LEFT) => {
             // (┤, ┤) => Some(┤)
-            let boundary_type = boundary_type::VERTICAL_LEFT;
+            let boundary_type = VERTICAL_LEFT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL_LEFT, boundary_type::VERTICAL_RIGHT) => {
+        (VERTICAL_LEFT, VERTICAL_RIGHT)
+        | (VERTICAL_LEFT, HORIZONTAL_DOWN)
+        | (VERTICAL_LEFT, HORIZONTAL_UP) => {
             // (┤, ├) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL_LEFT, boundary_type::HORIZONTAL_DOWN) => {
             // (┤, ┬) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL_LEFT, boundary_type::HORIZONTAL_UP) => {
             // (┤, ┴) => Some(┼)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL_LEFT, boundary_type::CROSS) => {
-            // (┤, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL_RIGHT, boundary_type::VERTICAL_RIGHT) => {
+        (VERTICAL_RIGHT, VERTICAL_RIGHT) => {
             // (├, ├) => Some(├)
-            let boundary_type = boundary_type::VERTICAL_RIGHT;
+            let boundary_type = VERTICAL_RIGHT;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::VERTICAL_RIGHT, boundary_type::HORIZONTAL_DOWN) => {
+        (VERTICAL_RIGHT, HORIZONTAL_DOWN) | (VERTICAL_RIGHT, HORIZONTAL_UP) => {
             // (├, ┬) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL_RIGHT, boundary_type::HORIZONTAL_UP) => {
             // (├, ┴) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::VERTICAL_RIGHT, boundary_type::CROSS) => {
-            // (├, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL_DOWN, boundary_type::HORIZONTAL_DOWN) => {
+        (HORIZONTAL_DOWN, HORIZONTAL_DOWN) => {
             // (┬, ┬) => Some(┬)
-            let boundary_type = boundary_type::HORIZONTAL_DOWN;
+            let boundary_type = HORIZONTAL_DOWN;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL_DOWN, boundary_type::HORIZONTAL_UP) => {
+        (HORIZONTAL_DOWN, HORIZONTAL_UP) => {
             // (┬, ┴) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
+            let boundary_type = CROSS;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL_DOWN, boundary_type::CROSS) => {
-            // (┬, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::HORIZONTAL_UP, boundary_type::HORIZONTAL_UP) => {
+        (HORIZONTAL_UP, HORIZONTAL_UP) => {
             // (┴, ┴) => Some(┴)
-            let boundary_type = boundary_type::HORIZONTAL_UP;
+            let boundary_type = HORIZONTAL_UP;
             Some(BoundarySymbol {
                 boundary_type,
                 invisible,
                 color,
             })
         }
-        (boundary_type::HORIZONTAL_UP, boundary_type::CROSS) => {
-            // (┴, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (boundary_type::CROSS, boundary_type::CROSS) => {
-            // (┼, ┼) => Some(┼)
-            let boundary_type = boundary_type::CROSS;
-            Some(BoundarySymbol {
-                boundary_type,
-                invisible,
-                color,
-            })
-        }
-        (_, _) => None,
-    }
-}
-
-fn find_next_symbol(
-    first_symbol: BoundarySymbol,
-    second_symbol: BoundarySymbol,
-) -> Option<BoundarySymbol> {
-    if let Some(symbol) = combine_symbols(first_symbol, second_symbol) {
-        Some(symbol)
-    } else {
-        combine_symbols(second_symbol, first_symbol)
+        (_, _) => combine_symbols(next_symbol, current_symbol),
     }
 }
 
@@ -791,7 +496,7 @@ impl Boundaries {
                 let next_symbol = self
                     .boundary_characters
                     .remove(&coordinates)
-                    .and_then(|current_symbol| find_next_symbol(current_symbol, symbol_to_add))
+                    .and_then(|current_symbol| combine_symbols(current_symbol, symbol_to_add))
                     .unwrap_or(symbol_to_add);
                 self.boundary_characters.insert(coordinates, next_symbol);
             }
@@ -815,7 +520,7 @@ impl Boundaries {
                 let next_symbol = self
                     .boundary_characters
                     .remove(&coordinates)
-                    .and_then(|current_symbol| find_next_symbol(current_symbol, symbol_to_add))
+                    .and_then(|current_symbol| combine_symbols(current_symbol, symbol_to_add))
                     .unwrap_or(symbol_to_add);
                 self.boundary_characters.insert(coordinates, next_symbol);
             }
@@ -840,7 +545,7 @@ impl Boundaries {
                 let next_symbol = self
                     .boundary_characters
                     .remove(&coordinates)
-                    .and_then(|current_symbol| find_next_symbol(current_symbol, symbol_to_add))
+                    .and_then(|current_symbol| combine_symbols(current_symbol, symbol_to_add))
                     .unwrap_or(symbol_to_add);
                 self.boundary_characters.insert(coordinates, next_symbol);
             }
@@ -864,7 +569,7 @@ impl Boundaries {
                 let next_symbol = self
                     .boundary_characters
                     .remove(&coordinates)
-                    .and_then(|current_symbol| find_next_symbol(current_symbol, symbol_to_add))
+                    .and_then(|current_symbol| combine_symbols(current_symbol, symbol_to_add))
                     .unwrap_or(symbol_to_add);
                 self.boundary_characters.insert(coordinates, next_symbol);
             }