diff --git a/src/filter/bsp_interior.rs b/src/filter/bsp_interior.rs
index b42f147..8999b9a 100644
--- a/src/filter/bsp_interior.rs
+++ b/src/filter/bsp_interior.rs
@@ -21,10 +21,10 @@
 //! 
 
 use rand::prelude::*;
-use super::MapFilter;
+use crate::MapFilter;
 use crate::geometry::{Point, Rect};
 use crate::random::Rng;
-use crate::map::Map;
+use crate::Map;
 
 
 pub struct BspInterior {
diff --git a/src/filter/bsp_rooms.rs b/src/filter/bsp_rooms.rs
index 8c6fa91..4df3248 100644
--- a/src/filter/bsp_rooms.rs
+++ b/src/filter/bsp_rooms.rs
@@ -19,10 +19,10 @@
 //! 
 
 use rand::prelude::*;
-use super::MapFilter;
+use crate::MapFilter;
 use crate::geometry::Rect;
 use crate::random::Rng;
-use crate::map::{Map, TileType};
+use crate::{Map, TileType};
 
 
 pub struct BspRooms {
diff --git a/src/filter/cellular_automata.rs b/src/filter/cellular_automata.rs
index a7df128..2a8332a 100644
--- a/src/filter/cellular_automata.rs
+++ b/src/filter/cellular_automata.rs
@@ -22,8 +22,8 @@
 //! 
 
 use rand::prelude::*;
-use super::MapFilter;
-use crate::map::{Map, TileType};
+use crate::MapFilter;
+use crate::{Map, TileType};
 
 
 /// Map generator and modifier
diff --git a/src/filter/cull_unreachable.rs b/src/filter/cull_unreachable.rs
index 159f6c8..e5b1390 100644
--- a/src/filter/cull_unreachable.rs
+++ b/src/filter/cull_unreachable.rs
@@ -5,8 +5,8 @@
 //! 
 
 use rand::prelude::StdRng;
-use super::MapFilter;
-use crate::map::{Map, TileType};
+use crate::MapFilter;
+use crate::{Map, TileType};
 use crate::dijkstra::DijkstraMap;
 
 
diff --git a/src/filter/distant_exit.rs b/src/filter/distant_exit.rs
index 0aa659f..498d577 100644
--- a/src/filter/distant_exit.rs
+++ b/src/filter/distant_exit.rs
@@ -7,8 +7,8 @@
 use std::f32;
 use rand::prelude::StdRng;
 use crate::geometry::Point;
-use super::MapFilter;
-use crate::map::Map;
+use crate::MapFilter;
+use crate::Map;
 use crate::dijkstra::DijkstraMap;
 
 
diff --git a/src/filter/drunkard.rs b/src/filter/drunkard.rs
index 607cc0c..3f028a6 100644
--- a/src/filter/drunkard.rs
+++ b/src/filter/drunkard.rs
@@ -14,7 +14,7 @@
 //! 
 
 use rand::prelude::*;
-use super::MapFilter;
+use crate::MapFilter;
 use crate::{
     map::{Map, Symmetry, TileType},
     geometry::Point,
diff --git a/src/filter/mod.rs b/src/filter/mod.rs
index 2b60d65..53e91bd 100644
--- a/src/filter/mod.rs
+++ b/src/filter/mod.rs
@@ -44,77 +44,5 @@ pub use distant_exit::DistantExit;
 pub use drunkard::DrunkardsWalk;
 pub use simple_rooms::SimpleRooms;
 pub use rooms_corridors_nearest::NearestCorridors;
-pub use starting_point::AreaStartingPosition;
+pub use starting_point::{AreaStartingPosition, XStart, YStart};
 
-use std::time::{SystemTime, UNIX_EPOCH};
-use rand::prelude::*;
-use crate::map::Map;
-
-
-/// Trait which should be implemented by map modifier. 
-/// Modifier takes initiall map and apply changes to it.
-pub trait MapFilter {
-    fn modify_map(&self, rng: &mut StdRng, map: &Map) -> Map;
-}
-
-/// Used to chain MapBuilder and MapModifiers to create the final map.
-pub struct MapBuilder {
-    modifiers: Vec<Box<dyn MapFilter>>,
-}
-
-impl MapBuilder {
-    /// Create Map Builder with initial map generator
-    pub fn new() -> MapBuilder {
-        MapBuilder { 
-            modifiers: Vec::new(),
-        }
-    }
-
-    pub fn with(&mut self, modifier : Box<dyn MapFilter>) -> &mut MapBuilder {
-        self.modifiers.push(modifier);
-        self
-    }
-
-    /// Build map using random number seeded with system time
-    pub fn build_map(&mut self, width: usize, height: usize) -> Map {
-        let system_time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Can't access system time");
-        let mut rng = StdRng::seed_from_u64(system_time.as_millis() as u64);
-        self.build_map_with_rng(width, height, &mut rng)
-    }
-
-    /// Build map using provided random number generator
-    pub fn build_map_with_rng(&mut self, width: usize, height: usize, rng: &mut StdRng) -> Map {
-        let mut map = Map::new(width, height);
-        
-        // Build additional layers in turn
-        for modifier in self.modifiers.iter() {
-            map = modifier.modify_map(rng, &map);
-        }
-
-        map
-    }
-
-}
-
-/// ------------------------------------------------------------------------------------------------
-/// Module unit tests
-/// ------------------------------------------------------------------------------------------------
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use cellular_automata::CellularAutomata;
-    use starting_point::{AreaStartingPosition, XStart, YStart};
-
-    #[test]
-    fn test_ca_map() {
-        let map = MapBuilder::new()
-            .with(CellularAutomata::new())
-            .with(AreaStartingPosition::new(XStart::CENTER, YStart::CENTER))
-            .build_map(80, 50);
-
-        assert_eq!(map.width, 80);
-        assert_eq!(map.height, 50);
-        assert_eq!(map.starting_point.is_some(), true);
-    }
-
-}
\ No newline at end of file
diff --git a/src/filter/rooms_corridors_nearest.rs b/src/filter/rooms_corridors_nearest.rs
index 0d92954..7bbe717 100644
--- a/src/filter/rooms_corridors_nearest.rs
+++ b/src/filter/rooms_corridors_nearest.rs
@@ -1,8 +1,8 @@
 //! Connect nearest rooms on the map with corridors
 //! 
 use rand::prelude::StdRng;
-use super::MapFilter;
-use crate::map::Map;
+use crate::MapFilter;
+use crate::Map;
 use std::collections::HashSet;
 
 
diff --git a/src/filter/simple_rooms.rs b/src/filter/simple_rooms.rs
index 24b7c4b..4335547 100644
--- a/src/filter/simple_rooms.rs
+++ b/src/filter/simple_rooms.rs
@@ -19,10 +19,10 @@
 //! 
 
 use rand::prelude::*;
-use super::MapFilter;
+use crate::MapFilter;
 use crate::geometry::Rect;
 use crate::random::Rng;
-use crate::map::{Map};
+use crate::Map;
 
 
 pub struct SimpleRooms {
diff --git a/src/filter/starting_point.rs b/src/filter/starting_point.rs
index 672e58c..e087846 100644
--- a/src/filter/starting_point.rs
+++ b/src/filter/starting_point.rs
@@ -21,9 +21,9 @@
 //! 
 
 use rand::prelude::StdRng;
-use super::MapFilter;
+use crate::MapFilter;
 use crate::geometry::Point;
-use crate::map::{Map, TileType};
+use crate::{Map, TileType};
 
 
 /// Initial x region position
diff --git a/src/lib.rs b/src/lib.rs
index 64f5b56..ef4e10e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,15 +1,108 @@
-//! A collection of map generators.
+//! Generators for dungeon type maps.
 //! 
-//! The generators are implemented for the following types of maps:
-//!   * Dungeon maps
+//! Generators can bu used directly or they can be combined with
+//! `MapGenerator`s and `MapModifier`s
 //! 
+//! * MapGenerators are use to create initial map.
+//! * MapModifiers modify existing map.
+//! 
+//! Example
+//! ```
+//! use mapgen::{MapFilter, MapBuilder, Map, TileType};
+//! use mapgen::filter::{
+//!     CellularAutomata,
+//!     starting_point::{AreaStartingPosition, XStart, YStart}
+//! };
+//! use mapgen::geometry::Point;
+//! 
+//! let map = MapBuilder::new()
+//!             .with(CellularAutomata::new())
+//!             .with(AreaStartingPosition::new(XStart::CENTER, YStart::CENTER))
+//!             .build_map(80, 50);
+//! 
+//! assert_eq!(map.width, 80);
+//! assert_eq!(map.height, 50);
+//! assert_eq!(map.starting_point.is_some(), true);
+//! ```
+//!  
  
 pub mod filter;
 pub mod geometry;
 pub mod map;
 
-pub use map::{Map, TileType};
-pub use filter::{MapFilter, MapBuilder};
+pub use map::{Map, Symmetry, TileType};
 
 pub (crate) mod dijkstra;
-pub (crate) mod random;
\ No newline at end of file
+pub (crate) mod random;
+
+use std::time::{SystemTime, UNIX_EPOCH};
+use rand::prelude::*;
+
+
+/// Trait which should be implemented by map modifier. 
+/// Modifier takes initiall map and apply changes to it.
+pub trait MapFilter {
+    fn modify_map(&self, rng: &mut StdRng, map: &Map) -> Map;
+}
+
+/// Used to chain MapBuilder and MapModifiers to create the final map.
+pub struct MapBuilder {
+    modifiers: Vec<Box<dyn MapFilter>>,
+}
+
+impl MapBuilder {
+    /// Create Map Builder with initial map generator
+    pub fn new() -> MapBuilder {
+        MapBuilder { 
+            modifiers: Vec::new(),
+        }
+    }
+
+    pub fn with(&mut self, modifier : Box<dyn MapFilter>) -> &mut MapBuilder {
+        self.modifiers.push(modifier);
+        self
+    }
+
+    /// Build map using random number seeded with system time
+    pub fn build_map(&mut self, width: usize, height: usize) -> Map {
+        let system_time = SystemTime::now().duration_since(UNIX_EPOCH).expect("Can't access system time");
+        let mut rng = StdRng::seed_from_u64(system_time.as_millis() as u64);
+        self.build_map_with_rng(width, height, &mut rng)
+    }
+
+    /// Build map using provided random number generator
+    pub fn build_map_with_rng(&mut self, width: usize, height: usize, rng: &mut StdRng) -> Map {
+        let mut map = Map::new(width, height);
+        
+        // Build additional layers in turn
+        for modifier in self.modifiers.iter() {
+            map = modifier.modify_map(rng, &map);
+        }
+
+        map
+    }
+
+}
+
+/// ------------------------------------------------------------------------------------------------
+/// Module unit tests
+/// ------------------------------------------------------------------------------------------------
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use filter::CellularAutomata;
+    use filter::{AreaStartingPosition, XStart, YStart};
+
+    #[test]
+    fn test_ca_map() {
+        let map = MapBuilder::new()
+            .with(CellularAutomata::new())
+            .with(AreaStartingPosition::new(XStart::CENTER, YStart::CENTER))
+            .build_map(80, 50);
+
+        assert_eq!(map.width, 80);
+        assert_eq!(map.height, 50);
+        assert_eq!(map.starting_point.is_some(), true);
+    }
+
+}
\ No newline at end of file