diff --git a/crates/servicepoint/src/byte_grid.rs b/crates/servicepoint/src/byte_grid.rs
index 163237a..d6d5759 100644
--- a/crates/servicepoint/src/byte_grid.rs
+++ b/crates/servicepoint/src/byte_grid.rs
@@ -43,10 +43,6 @@ impl ByteGrid {
         }
     }
 
-    fn is_position_valid(&self, x: isize, y: isize) -> bool {
-        x > 0 && x < self.width as isize && y > 0 && y < self.height as isize
-    }
-
     fn check_indexes(&self, x: usize, y: usize) {
         assert!(
             x < self.width,
@@ -96,22 +92,6 @@ impl Grid<u8> for ByteGrid {
         self.data[x + y * self.width]
     }
 
-    fn get_optional(&self, x: isize, y: isize) -> Option<u8> {
-        if self.is_position_valid(x, y) {
-            Some(self.get(x as usize, y as usize))
-        } else {
-            None
-        }
-    }
-
-    fn set_optional(&mut self, x: isize, y: isize, value: u8) -> Option<u8> {
-        if self.is_position_valid(x, y) {
-            Some(self.set(x as usize, y as usize, value))
-        } else {
-            None
-        }
-    }
-
     fn fill(&mut self, value: u8) {
         self.data.fill(value);
     }
@@ -151,7 +131,7 @@ impl RefGrid<u8> for ByteGrid {
     }
 
     fn get_ref_optional(&self, x: isize, y: isize) -> Option<&u8> {
-        if self.is_position_valid(x, y) {
+        if self.is_in_bounds(x, y) {
             Some(&self.data[x as usize + y as usize * self.width])
         } else {
             None
@@ -164,7 +144,7 @@ impl RefGrid<u8> for ByteGrid {
     }
 
     fn get_ref_mut_optional(&mut self, x: isize, y: isize) -> Option<&mut u8> {
-        if self.is_position_valid(x, y) {
+        if self.is_in_bounds(x, y) {
             Some(&mut self.data[x as usize + y as usize * self.width])
         } else {
             None
diff --git a/crates/servicepoint/src/grid.rs b/crates/servicepoint/src/grid.rs
index 79cdbfb..76c80db 100644
--- a/crates/servicepoint/src/grid.rs
+++ b/crates/servicepoint/src/grid.rs
@@ -31,7 +31,13 @@ pub trait Grid<T> {
     /// * `x` and `y`: position of the cell to read
     ///
     /// returns: Value at position or None
-    fn get_optional(&self, x: isize, y: isize) -> Option<T>;
+    fn get_optional(&self, x: isize, y: isize) -> Option<T> {
+        if self.is_in_bounds(x, y) {
+            Some(self.get(x as usize, y as usize))
+        } else {
+            None
+        }
+    }
 
     /// Sets the value at the specified position if the position is inside of bounds
     ///
@@ -40,7 +46,13 @@ pub trait Grid<T> {
     /// * `x` and `y`: position of the cell to read
     ///
     /// returns: the old value or None
-    fn set_optional(&mut self, x: isize, y: isize, value: T) -> Option<T>;
+    fn set_optional(&mut self, x: isize, y: isize, value: T) -> Option<T> {
+        if self.is_in_bounds(x, y) {
+            Some(self.set(x as usize, y as usize, value))
+        } else {
+            None
+        }
+    }
 
     /// Sets all cells in the grid to the specified value
     fn fill(&mut self, value: T);
@@ -50,6 +62,14 @@ pub trait Grid<T> {
 
     /// the height in y-direction
     fn height(&self) -> usize;
+
+    /// Checks whether the specified position is
+    fn is_in_bounds(&self, x: isize, y: isize) -> bool {
+        x > 0
+            && x < self.width() as isize
+            && y > 0
+            && y < self.height() as isize
+    }
 }
 
 /// A grid that can return cells as references.
diff --git a/crates/servicepoint/src/pixel_grid.rs b/crates/servicepoint/src/pixel_grid.rs
index e6a3840..c6d02dd 100644
--- a/crates/servicepoint/src/pixel_grid.rs
+++ b/crates/servicepoint/src/pixel_grid.rs
@@ -60,10 +60,6 @@ impl PixelGrid {
         }
     }
 
-    fn is_position_valid(&self, x: isize, y: isize) -> bool {
-        x > 0 && x < self.width as isize && y > 0 && y < self.height as isize
-    }
-
     fn check_indexes(&self, x: usize, y: usize) {
         assert!(
             x < self.width,
@@ -100,27 +96,6 @@ impl Grid<bool> for PixelGrid {
         self.bit_vec.get(x + y * self.width)
     }
 
-    fn get_optional(&self, x: isize, y: isize) -> Option<bool> {
-        if self.is_position_valid(x, y) {
-            Some(self.get(x as usize, y as usize))
-        } else {
-            None
-        }
-    }
-
-    fn set_optional(
-        &mut self,
-        x: isize,
-        y: isize,
-        value: bool,
-    ) -> Option<bool> {
-        if self.is_position_valid(x, y) {
-            Some(self.set(x as usize, y as usize, value))
-        } else {
-            None
-        }
-    }
-
     /// Sets the state of all pixels in the `PixelGrid`.
     ///
     /// # Arguments