diff --git a/core.adb b/core.adb
index 7283199..21f4830 100644
--- a/core.adb
+++ b/core.adb
@@ -12,60 +12,60 @@
 
 with ada.text_io;
 
-package core is
+package body core is
 
                                              ------------------------------------------------------------------------------------------
 
-	procedure delete is
+	procedure screen_delete is
 	begin
 		ada.text_io.put (escape & "[2J");
-	end delete;
+	end screen_delete;
 
-	procedure offset is
+	procedure screen_offset is
 	begin
 		ada.text_io.put (escape & "[H");
-	end offset;
+	end screen_offset;
 
-	procedure hide_cursor is
+	procedure screen_hide_cursor is
 	begin
 		ada.text_io.put (escape & "[?25l");
-	end hide_cursor;
+	end screen_hide_cursor;
 
-	procedure show_cursor is
+	procedure screen_show_cursor is
 	begin
 		ada.text_io.put (escape & "[?25h");
-	end show_cursor;
+	end screen_show_cursor;
 
-	procedure new_line is
+	procedure screen_new_line is
 	begin
 		ada.text_io.put (carriage_return & line_feed);
-	end new_line;
+	end screen_new_line;
 
-	procedure render_character (symbol : character := ' ';
-	                            colour : character := colour.white;
-	                            effect : character := effect.normal;
-	                            y      : height    := 0;
-	                            x      : width     := 0) is
+	procedure render_character (symbol : character     := ' ';
+	                            colour : character     := '7';
+	                            effect : character     := '0';
+	                            y      : screen_height := 0;
+	                            x      : screen_width  := 0) is
 	begin
-		symbol_matrix (y, x) := symbol;
-		colour_matrix (y, x) := colour;
-		effect_matrix (y, x) := effect;
+		screen_symbol (y, x) := symbol;
+		screen_colour (y, x) := colour;
+		screen_effect (y, x) := effect;
 	end render_character;
 
 	procedure render_buffer is
 		format : string (1 .. 12) := escape & "[E;3CmS" & escape & "[0m";
 	begin
-		offset;
-		for y in height
+		screen_offset;
+		for y in screen_height
 		loop
-			for x in width
+			for x in screen_width
 			loop
-				format (8) := symbol_matrix (y, x);
-				format (6) := colour_matrix (y, x);
-				format (3) := effect_matrix (y, x);
+				format (8) := screen_symbol (y, x);
+				format (6) := screen_colour (y, x);
+				format (3) := screen_effect (y, x);
 				ada.text_io.put (format);
 			end loop;
-			new_line;
+			screen_new_line;
 		end loop;
 	end render_buffer;
 
diff --git a/main.adb b/main.adb
index f414ed1..b828dc2 100644
--- a/main.adb
+++ b/main.adb
@@ -12,7 +12,7 @@
 
 with ada.text_io;
 
-with core, action, screen, map, item, magic, ammunition, weapon, armour, plant, animal, monster, player;
+with core, action, map, item, magic, ammunition, weapon, armour, plant, animal, monster, player;
 
 function main return integer is
 
@@ -164,19 +164,19 @@ begin
 	action.bind ('a', player.move_left'access);
 	action.bind ('d', player.move_right'access);
 
-	screen.delete;
-	screen.offset;
-	screen.hide_cursor;
+	core.screen_delete;
+	core.screen_offset;
+	core.screen_hide_cursor;
 
-	generate_map;
+	map.generate;
 
                                              ------------------------------------------------------------------------------------------
 
 	loop
 		action.signal := core.cancel;
-		render_map;
+		map.render;
 		player.render;
-		screen.render_buffer;
+		core.render_buffer;
 		ada.text_io.get_immediate (action.signal);
 		action.list (character'pos (action.signal)).all;
 		exit when action.active = false;
@@ -184,7 +184,7 @@ begin
 
                                              ------------------------------------------------------------------------------------------
 
-	screen.show_cursor;
+	core.screen_show_cursor;
 
 	return 0;
 
diff --git a/map.adb b/map.adb
index 8020be0..4c371e3 100644
--- a/map.adb
+++ b/map.adb
@@ -10,7 +10,7 @@
 -- write a new program in Ada, a tiny game. Work in progress, it's messy and ugly for now...
 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
-with core, screen;
+with core;
 
 package body map is
 
@@ -22,7 +22,7 @@ package body map is
 		loop
 			for x in width
 			loop
-				map_matrical_data (y, x) := (MAP_WOODEN_FLOOR, map_constant_data (MAP_WOODEN_FLOOR).condition_limit);
+				matrical_data (y, x) := (MAP_WOODEN_FLOOR, constant_data (MAP_WOODEN_FLOOR).condition_limit);
 			end loop;
 		end loop;
 	end generate;
@@ -32,14 +32,14 @@ package body map is
 		colour : character := core.colour.white;
 		effect : character := core.effect.normal;
 	begin
-		for y in screen.height
+		for y in core.screen_height
 		loop
-			for x in screen.width
+			for x in core.screen_width
 			loop
-				symbol := map_constant_data (map_matrical_data (map_height (y), map_width (x)).map).symbol;
-				colour := map_constant_data (map_matrical_data (map_height (y), map_width (x)).map).colour;
-				effect := map_constant_data (map_matrical_data (map_height (y), map_width (x)).map).effect;
-				screen.render_character (symbol, colour, effect, y, x);
+				symbol := constant_data (matrical_data (height (y), width (x)).map).symbol;
+				colour := constant_data (matrical_data (height (y), width (x)).map).colour;
+				effect := constant_data (matrical_data (height (y), width (x)).map).effect;
+				core.render_character (symbol, colour, effect, y, x);
 			end loop;
 		end loop;
 	end render;
diff --git a/player.adb b/player.adb
index 10a5c78..3361deb 100644
--- a/player.adb
+++ b/player.adb
@@ -10,17 +10,18 @@
 -- write a new program in Ada, a tiny game. Work in progress, it's messy and ugly for now...
 ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 
-with core, screen;
-
-use screen;
+with core;
 
 package body player is
 
                                              ------------------------------------------------------------------------------------------
 
+	use type core.screen_width;
+	use type core.screen_height;
+
 	procedure render is
 	begin
-		screen.render_character ('@', core.colour.cyan, core.effect.bold, screen.height (data.y), screen.width (data.x));
+		core.render_character ('@', core.colour.cyan, core.effect.bold, core.screen_height (data.y), core.screen_width (data.x));
 	end render;
 
 	procedure move_up is