diff --git a/include/block.hpp b/include/block.hpp
index 7dedbfb..4081da6 100644
--- a/include/block.hpp
+++ b/include/block.hpp
@@ -36,7 +36,7 @@ public:
     /**
      * Appelé lorsque le bloc est activé par un objet
      */
-    virtual void activated(Object& object);
+    virtual void activated(Level& level, Object& object);
 
     /**
      * Récupère l'identifiant de type des blocs
diff --git a/include/gravity_block.hpp b/include/gravity_block.hpp
new file mode 100644
index 0000000..199f341
--- /dev/null
+++ b/include/gravity_block.hpp
@@ -0,0 +1,51 @@
+#ifndef __PTF_GRAVITY_BLOCK_HPP__
+#define __PTF_GRAVITY_BLOCK_HPP__
+
+#include "block.hpp"
+#include "level.hpp"
+
+class GravityBlock : public Block {
+private:
+    GravityDirection gravity_direction;
+
+public:
+    /**
+     * Identifiant unique du type "bloc de gravité"
+     */
+    static const unsigned int TYPE_ID;
+
+    GravityBlock();
+    virtual ~GravityBlock();
+
+    /**
+     * Clone ce bloc de gravité en un bloc de gravité avec les mêmes propriétés
+     */
+    virtual ObjectPtr clone() const;
+
+    /**
+     * Appelé lorsque le bloc de gravité est activé par un objet
+     */
+    virtual void activated(Level& level, Object& object);
+
+    /**
+     * Récupère l'identifiant de type des blocs de gravité
+     */
+    virtual unsigned int getTypeId() const;
+
+    /**
+     * Chargement du bloc de gravité depuis le fichier donné
+     */
+    static ObjectPtr load(std::ifstream& file);
+
+    /**
+     * Récupère la direction de gravité du bloc changeur de gravité
+     */
+    GravityDirection getGravityDirection() const;
+
+    /**
+     * Modifie la direction de gravité du bloc
+     */
+    void setGravityDirection(GravityDirection set_gravity_direction);
+};
+
+#endif
diff --git a/include/level.hpp b/include/level.hpp
index 3bdb22d..9a8d67e 100644
--- a/include/level.hpp
+++ b/include/level.hpp
@@ -115,7 +115,7 @@ public:
     /**
      * Modifie la direction de la gravité
      */
-    void setGravity(GravityDirection direction);
+    void setGravityDirection(GravityDirection direction);
 
     /**
      * Récupère la liste des objets
diff --git a/include/object.hpp b/include/object.hpp
index 61e8e0f..5757e4a 100644
--- a/include/object.hpp
+++ b/include/object.hpp
@@ -66,7 +66,7 @@ public:
     /**
      * Appelé lorsque l'objet est activé par un autre
      */
-    virtual void activated(Object& object) = 0;
+    virtual void activated(Level& level, Object& object) = 0;
 
     /**
      * Récupère l'identifiant de type de cet objet
@@ -102,7 +102,7 @@ public:
      * et l'objet passé en paramètre selon la normale
      * donnée
      */
-    virtual void solveCollision(Object& obj, const sf::Vector2f& normal);
+    virtual void solveCollision(Level& level, Object& obj, const sf::Vector2f& normal);
 
     /**
      * Application de la correction positionnelle sur
diff --git a/include/player.hpp b/include/player.hpp
index 36ec109..b37a226 100644
--- a/include/player.hpp
+++ b/include/player.hpp
@@ -42,7 +42,7 @@ public:
     /**
      * Appelé lorsque le joueur est activé par un objet
      */
-    virtual void activated(Object& object);
+    virtual void activated(Level& level, Object& object);
 
     /**
      * Récupère l'identifiant de type des joueurs
diff --git a/levels/level1.dat b/levels/level1.dat
index 9093f3b..72e63c0 100644
Binary files a/levels/level1.dat and b/levels/level1.dat differ
diff --git a/src/block.cpp b/src/block.cpp
index a62f05b..acd7c2a 100644
--- a/src/block.cpp
+++ b/src/block.cpp
@@ -37,7 +37,7 @@ void Block::draw(Level& level) {
     ResourceManager& resources = level.getResourceManager();
     sf::RenderWindow& window = level.getWindow();
 
-    sprite.setTexture(resources.getTexture("block.png"));
+    sprite.setTexture(resources.getTexture("block.tga"));
     select_sprite.setTexture(resources.getTexture("block_select.png"));
 
     // coloration du bloc en fonction de sa charge
@@ -59,7 +59,7 @@ void Block::draw(Level& level) {
     }
 }
 
-void Block::activated(Object& object) {
+void Block::activated(Level& level, Object& object) {
     // ne rien faire si le bloc est activé.
     // Ceci est un bloc de base qui n'a pas a réagir
     // aux activations
diff --git a/src/collision.cpp b/src/collision.cpp
index 87ee419..18c49ce 100644
--- a/src/collision.cpp
+++ b/src/collision.cpp
@@ -1,6 +1,7 @@
 #include "collision.hpp"
 #include "player.hpp"
 #include "block.hpp"
+#include "gravity_block.hpp"
 #include "object.hpp"
 #include <functional>
 #include <utility>
@@ -189,10 +190,15 @@ std::map<
     std::pair<unsigned int, unsigned int>,
     std::function<bool(CollisionData&)>
 > collision_map = {
-    {std::make_pair(Player::TYPE_ID, Block::TYPE_ID), playerToBlock},
-    {std::make_pair(Block::TYPE_ID, Player::TYPE_ID), blockToPlayer},
     {std::make_pair(Player::TYPE_ID, Player::TYPE_ID), playerToPlayer},
-    {std::make_pair(Block::TYPE_ID, Block::TYPE_ID), blockToBlock}
+    {std::make_pair(Player::TYPE_ID, Block::TYPE_ID), playerToBlock},
+    {std::make_pair(Player::TYPE_ID, GravityBlock::TYPE_ID), playerToBlock},
+    {std::make_pair(Block::TYPE_ID, Block::TYPE_ID), blockToBlock},
+    {std::make_pair(Block::TYPE_ID, GravityBlock::TYPE_ID), blockToBlock},
+    {std::make_pair(Block::TYPE_ID, Player::TYPE_ID), blockToPlayer},
+    {std::make_pair(GravityBlock::TYPE_ID, Block::TYPE_ID), blockToBlock},
+    {std::make_pair(GravityBlock::TYPE_ID, GravityBlock::TYPE_ID), blockToBlock},
+    {std::make_pair(GravityBlock::TYPE_ID, Player::TYPE_ID), blockToPlayer}
 };
 
 CollisionData::CollisionData(Object& objA, Object& objB) :
diff --git a/src/editor.cpp b/src/editor.cpp
index 21149ce..d032381 100644
--- a/src/editor.cpp
+++ b/src/editor.cpp
@@ -18,9 +18,16 @@ Editor::Editor(Manager& manager) : Level(manager), drag_mode(DragMode::NONE),
     setTotalTime(30);
 
     ResourceManager& resources = getResourceManager();
-    std::shared_ptr<SelectorCategory> basic = widget_selector.addCategory("BASE");
-    basic->addItem("Block", resources.getTexture("block.png"));
-    basic->addItem("Player", resources.getTexture("player.tga"));
+
+    std::shared_ptr<SelectorCategory> basic_cat = widget_selector.addCategory("BASE");
+    basic_cat->addItem("Block", resources.getTexture("block.tga"));
+    basic_cat->addItem("Player", resources.getTexture("player.tga"));
+
+    std::shared_ptr<SelectorCategory> gravity_cat = widget_selector.addCategory(sf::String(L"GRAVITÉ"));
+    gravity_cat->addItem("GravityN", resources.getTexture("gravity_block_north.tga"));
+    gravity_cat->addItem("GravityE", resources.getTexture("gravity_block_east.tga"));
+    gravity_cat->addItem("GravityS", resources.getTexture("gravity_block_south.tga"));
+    gravity_cat->addItem("GravityW", resources.getTexture("gravity_block_west.tga"));
 }
 
 Editor::~Editor() {}
diff --git a/src/game.cpp b/src/game.cpp
index 459d7a1..7d11f82 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -111,7 +111,7 @@ void Game::update() {
     // résolution des collisions détectées
     for (unsigned int i = 0; i < colliding.size(); i++) {
         CollisionData& collided = colliding[i];
-        collided.objA.solveCollision(collided.objB, collided.normal);
+        collided.objA.solveCollision(*this, collided.objB, collided.normal);
     }
 
     // intégration de la vitesse dans la position
diff --git a/src/gravity_block.cpp b/src/gravity_block.cpp
new file mode 100644
index 0000000..3b19adc
--- /dev/null
+++ b/src/gravity_block.cpp
@@ -0,0 +1,47 @@
+#include "gravity_block.hpp"
+#include "level.hpp"
+
+const unsigned int GravityBlock::TYPE_ID = 3;
+
+GravityBlock::GravityBlock() : Block() {}
+GravityBlock::~GravityBlock() {}
+
+ObjectPtr GravityBlock::clone() const {
+    return ObjectPtr(new GravityBlock(*this));
+}
+
+void GravityBlock::activated(Level& level, Object& object) {
+    Block::activated(level, object);
+
+    // lorsque le bloc est activé, il transmet son
+    // sens de gravité au niveau
+    level.setGravityDirection(gravity_direction);
+}
+
+unsigned int GravityBlock::getTypeId() const {
+    return TYPE_ID;
+}
+
+ObjectPtr GravityBlock::load(std::ifstream& file) {
+    ObjectPtr object = ObjectPtr(new GravityBlock);
+    std::shared_ptr<GravityBlock> block = std::dynamic_pointer_cast<GravityBlock>(object);
+
+    // lecture de la direction de la gravité
+    char gravity_direction;
+    file.read(&gravity_direction, 1);
+    block->setGravityDirection((GravityDirection) gravity_direction);
+
+    // lecture des propriétés communes des objets
+    Object::load(file, object);
+    file.seekg(1, file.cur);
+
+    return object;
+}
+
+GravityDirection GravityBlock::getGravityDirection() const {
+    return gravity_direction;
+}
+
+void GravityBlock::setGravityDirection(GravityDirection set_gravity_direction) {
+    gravity_direction = set_gravity_direction;
+}
diff --git a/src/level.cpp b/src/level.cpp
index fe6ea32..d669660 100644
--- a/src/level.cpp
+++ b/src/level.cpp
@@ -1,11 +1,12 @@
 #include "constants.hpp"
-#include "block.hpp"
+#include "level.hpp"
 #include "player.hpp"
+#include "block.hpp"
+#include "gravity_block.hpp"
 #include <arpa/inet.h>
 #include <cstring>
 #include <queue>
 #include <utility>
-#include "level.hpp"
 
 const float GRAVITY = 235;
 
@@ -16,7 +17,8 @@ const float GRAVITY = 235;
  */
 std::map<unsigned int, std::function<ObjectPtr(std::ifstream&)>> object_type_map = {
     {Player::TYPE_ID, Player::load},
-    {Block::TYPE_ID, Block::load}
+    {Block::TYPE_ID, Block::load},
+    {GravityBlock::TYPE_ID, GravityBlock::load}
 };
 
 Level::Level(Manager& manager) : View(manager), gravity(0, GRAVITY) {}
@@ -196,21 +198,21 @@ sf::Vector2f Level::getGravity() const {
     return gravity;
 }
 
-void Level::setGravity(GravityDirection direction) {
+void Level::setGravityDirection(GravityDirection direction) {
     switch (direction) {
     case GravityDirection::NORTH:
         gravity = sf::Vector2f(0, -GRAVITY);
         break;
 
-    case GravityDirection::WEST:
+    case GravityDirection::EAST:
         gravity = sf::Vector2f(GRAVITY, 0);
         break;
 
     case GravityDirection::SOUTH:
-        gravity = sf::Vector2f(0, GRAVITY);
+        gravity = sf::Vector2f(0, -GRAVITY);
         break;
 
-    case GravityDirection::EAST:
+    case GravityDirection::WEST:
         gravity = sf::Vector2f(-GRAVITY, 0);
         break;
     }
diff --git a/src/object.cpp b/src/object.cpp
index 474d7c2..3f1b17c 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -154,7 +154,7 @@ bool Object::detectCollision(const Object& obj, CollisionData& data) const {
     return getCollisionData(data);
 }
 
-void Object::solveCollision(Object& obj, const sf::Vector2f& normal) {
+void Object::solveCollision(Level& level, Object& obj, const sf::Vector2f& normal) {
     // si les deux objets sont de masse infinie, réinitialisation
     // des vitesses en tant que collision
     if (getMassInvert() == 0 && obj.getMassInvert() == 0) {
@@ -174,8 +174,8 @@ void Object::solveCollision(Object& obj, const sf::Vector2f& normal) {
 
     // en ce point, on est bertins qu'une collision a eu lieu.
     // activation réciproque des deux objets
-    activated(obj);
-    obj.activated(*this);
+    activated(level, obj);
+    obj.activated(level, *this);
 
     // on utilise le plus petit coefficient de friction entre les
     // deux objets comme le coefficient de la collision
diff --git a/src/player.cpp b/src/player.cpp
index a9114d4..56cfd95 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -86,7 +86,7 @@ void Player::draw(Level& level) {
     level.getWindow().draw(sprite);
 }
 
-void Player::activated(Object& object) {
+void Player::activated(Level& level, Object& object) {
     // ne rien faire si le joueur est activé.
     // en règle générale, c'est l'objet activé par le joueur
     // qui s'occupe de la réponse
diff --git a/src/util/widget_selector.cpp b/src/util/widget_selector.cpp
index 0526528..b2200bc 100644
--- a/src/util/widget_selector.cpp
+++ b/src/util/widget_selector.cpp
@@ -63,6 +63,8 @@ void WidgetSelector::draw(sf::Vector2f position, sf::Vector2f size) {
     background.setPosition(position);
     window.draw(background);
 
+    float total_y = PADDING;
+
     for (unsigned int i = 0; i < categories.size(); i++) {
         std::shared_ptr<SelectorCategory> category = categories[i];
 
@@ -75,22 +77,25 @@ void WidgetSelector::draw(sf::Vector2f position, sf::Vector2f size) {
         category_label.setColor(sf::Color::Black);
         category_label.setPosition(position + sf::Vector2f(
             floor(size.x / 2 - category_label.getGlobalBounds().width / 2),
-            PADDING
+            total_y
         ));
 
         window.draw(category_label);
 
         for (unsigned int j = 0; j < category->items.size(); j++) {
+            total_y += PADDING + 24;
+
             std::shared_ptr<SelectorItem> item = category->items[j];
             sf::Vector2f sprite_position = position + sf::Vector2f(
                 size.x / 2 - item->sprite.getGlobalBounds().width / 2,
-                PADDING + 24 + 38 * j
+                total_y
             );
 
             // affichage du sprite de l'item
             item->sprite.setPosition(sprite_position);
             window.draw(item->sprite);
         }
-    }
 
+        total_y += 64;
+    }
 }