diff --git a/doc/class_diagramm_core.png b/doc/class_diagramm_core.png
index 1e9e8e7..89b7726 100644
Binary files a/doc/class_diagramm_core.png and b/doc/class_diagramm_core.png differ
diff --git a/doc/class_diagramm_pieces.png b/doc/class_diagramm_pieces.png
index a965a8c..a4ccf14 100644
Binary files a/doc/class_diagramm_pieces.png and b/doc/class_diagramm_pieces.png differ
diff --git a/src/Core/Bag.cpp b/src/Core/Bag.cpp
index 5c8d92e..f7edb6e 100644
--- a/src/Core/Bag.cpp
+++ b/src/Core/Bag.cpp
@@ -8,7 +8,7 @@
 #include <cstdlib>
 
 
-Bag::Bag(std::shared_ptr<PiecesList> piecesList) :
+Bag::Bag(const std::shared_ptr<PiecesList>& piecesList) :
     piecesList(piecesList) {
         
     // initialize bags
diff --git a/src/Core/Bag.h b/src/Core/Bag.h
index d780bbc..9a6b76f 100644
--- a/src/Core/Bag.h
+++ b/src/Core/Bag.h
@@ -23,7 +23,7 @@ class Bag {
         /**
          * Creates a new bag with the pieces currently selected in the piece list
          */
-        Bag(std::shared_ptr<PiecesList> piecesList);
+        Bag(const std::shared_ptr<PiecesList>& piecesList);
 
         /**
          * Ignores the remaining pieces in the current bag and startd fresh from a new bag
diff --git a/src/Core/GameBoard.cpp b/src/Core/GameBoard.cpp
index 37af858..e32a5b2 100644
--- a/src/Core/GameBoard.cpp
+++ b/src/Core/GameBoard.cpp
@@ -38,7 +38,7 @@ void GameBoard::initialize() {
 }
 
 bool GameBoard::moveLeft() {
-    if (this->isActivePieceInWall(Position{-1, 0})) {
+    if (this->activePieceInWall(Position{-1, 0})) {
         return false;
     }
     else {
@@ -49,7 +49,7 @@ bool GameBoard::moveLeft() {
 }
 
 bool GameBoard::moveRight() {
-    if (this->isActivePieceInWall(Position{1, 0})) {
+    if (this->activePieceInWall(Position{1, 0})) {
         return false;
     }
     else {
@@ -60,7 +60,7 @@ bool GameBoard::moveRight() {
 }
 
 bool GameBoard::moveDown() {
-    if (this->isActivePieceInWall(Position{0, -1})) {
+    if (this->activePieceInWall(Position{0, -1})) {
         return false;
     }
     else {
@@ -75,7 +75,7 @@ bool GameBoard::rotate(Rotation rotation) {
     this->rotate(rotation);
 
     // before trying to kick, check if the piece can rotate without kicking
-    if (!this->isActivePieceInWall()) {
+    if (!this->activePieceInWall()) {
         this->isLastMoveKick = false;
         return true;
     }
@@ -123,11 +123,11 @@ bool GameBoard::tryKicking(bool testingBottom, const std::set<Position>& safePos
             // check right before right arbitrarly, we don't decide this with rotations since it would still be arbitrary with 180° rotations
             if (overlapsRight) {
                 Position shift{+i, j};
-                if (!this->activePieceOverlapsOnePosition(safePositions, shift)) {
+                if (!this->activePieceOverlaps(safePositions, shift)) {
                     overlapsLeft = false;
                 }
                 else {
-                    if (!this->isActivePieceInWall(shift)) {
+                    if (!this->activePieceInWall(shift)) {
                         this->activePiecePosition += shift;
                         return true;
                     }
@@ -137,11 +137,11 @@ bool GameBoard::tryKicking(bool testingBottom, const std::set<Position>& safePos
             // do the same on the left side
             if (overlapsLeft) {
                 Position shift{-i, j};
-                if (!this->activePieceOverlapsOnePosition(safePositions, shift)) {
+                if (!this->activePieceOverlaps(safePositions, shift)) {
                     overlapsLeft = false;
                 }
                 else {
-                    if (!this->isActivePieceInWall(shift)) {
+                    if (!this->activePieceInWall(shift)) {
                         this->activePiecePosition += shift;
                         return true;
                     }
@@ -181,11 +181,11 @@ bool GameBoard::hold(Rotation initialRotation) {
     this->rotate(initialRotation);
 
     // if the piece can't spawn, abort initial rotation
-    if (this->isActivePieceInWall()) {
+    if (this->activePieceInWall()) {
         this->activePiece = std::make_shared<Piece>(stored);
         
         // if the piece still can't spawn, abort holding
-        if (this->isActivePieceInWall()) {
+        if (this->activePieceInWall()) {
             if (isFirstTimeHolding) {
                 this->activePiece = nullptr;
             }
@@ -219,16 +219,16 @@ bool GameBoard::spawnNextPiece() {
     // this piece has done nothing yet
     this->isLastMoveKick = false;
 
-    return !this->isActivePieceInWall();
+    return !this->activePieceInWall();
 }
 
 bool GameBoard::touchesGround() {
-    return this->isActivePieceInWall(Position{0, -1});
+    return this->activePieceInWall(Position{0, -1});
 }
 
 LineClear GameBoard::lockPiece() {
-    bool isLockedInPlace = (this->isActivePieceInWall(Position{0, 1}) && this->isActivePieceInWall(Position{1, 0})
-        && this->isActivePieceInWall(Position{-1, 0}) && this->isActivePieceInWall(Position{0, -1}));
+    bool isLockedInPlace = (this->activePieceInWall(Position{0, 1}) && this->activePieceInWall(Position{1, 0})
+        && this->activePieceInWall(Position{-1, 0}) && this->activePieceInWall(Position{0, -1}));
 
     for (Position position : this->activePiece->getPositions()) {
         this->board.changeBlock(position + this->activePiecePosition, this->activePiece->getBlockType());
@@ -268,14 +268,14 @@ std::vector<Piece> GameBoard::getNextPieces() const {
     return this->nextQueue;
 }
 
-bool GameBoard::isActivePieceInWall(const Position& shift) const {
+bool GameBoard::activePieceInWall(const Position& shift) const {
     for (Position position : this->activePiece->getPositions()) {
         if (this->board.getBlock(position + this->activePiecePosition + shift) != NOTHING) return true;
     }
     return false;
 }
 
-bool GameBoard::activePieceOverlapsOnePosition(const std::set<Position>& safePositions, const Position& shift) const {
+bool GameBoard::activePieceOverlaps(const std::set<Position>& safePositions, const Position& shift) const {
     for (Position position : this->activePiece->getPositions()) {
         if (safePositions.contains(position + this->activePiecePosition + shift)) return true;
     }
diff --git a/src/Core/GameBoard.h b/src/Core/GameBoard.h
index 7ce5fd8..68e8137 100644
--- a/src/Core/GameBoard.h
+++ b/src/Core/GameBoard.h
@@ -132,13 +132,13 @@ class GameBoard {
          * Checks if one of the active piece's positions touches a wall in the board
          * @return If the active piece is in a wall
          */
-        bool isActivePieceInWall(const Position& shift = Position{0, 0}) const;
+        bool activePieceInWall(const Position& shift = Position{0, 0}) const;
 
         /**
          * Check if one of the active piece's positions shifted by a specified position would overlap with a set of positions
          * @return If the shifted active piece overlaps with one of the position
          */
-        bool activePieceOverlapsOnePosition(const std::set<Position>& safePositions, const Position& shift = Position{0, 0}) const;
+        bool activePieceOverlaps(const std::set<Position>& safePositions, const Position& shift = Position{0, 0}) const;
         
         /**
          * Sets the active piece to its spawn position
diff --git a/src/Core/Menu.h b/src/Core/Menu.h
index 41331bc..5268a7e 100644
--- a/src/Core/Menu.h
+++ b/src/Core/Menu.h
@@ -14,8 +14,8 @@ class Menu {
     private:
         PiecesList piecesList; // the list of pieces in the game
         Player playerControls; // the controls of the player
-        int boardHeight;       // the height of the board for the next game
         int boardWidth;        // the width of the board for the next game
+        int boardHeight;       // the height of the board for the next game
 
     public:
         /**
diff --git a/src/Core/PiecesList.cpp b/src/Core/PiecesList.cpp
index 4e639d3..58474df 100644
--- a/src/Core/PiecesList.cpp
+++ b/src/Core/PiecesList.cpp
@@ -101,7 +101,7 @@ std::vector<std::pair<int, int>> PiecesList::getSelectedPieces() const {
     return this->selectedPieces;
 }
 
-Piece PiecesList::getPiece(std::pair<int, int> pieceIndex) const {
+Piece PiecesList::getPiece(const std::pair<int, int>& pieceIndex) const {
     return this->loadedPieces.at(pieceIndex.first).at(pieceIndex.second);
 }
 
diff --git a/src/Core/PiecesList.h b/src/Core/PiecesList.h
index bd524e8..5f26216 100644
--- a/src/Core/PiecesList.h
+++ b/src/Core/PiecesList.h
@@ -84,7 +84,7 @@ class PiecesList {
         /**
          * @return The piece corresponding to the specified index
          */
-        Piece getPiece(std::pair<int, int> pieceIndex) const;
+        Piece getPiece(const std::pair<int, int>& pieceIndex) const;
     
     private:
         /**
diff --git a/src/Core/main.cpp b/src/TextUI/main.cpp
similarity index 99%
rename from src/Core/main.cpp
rename to src/TextUI/main.cpp
index cf36506..ba933d2 100644
--- a/src/Core/main.cpp
+++ b/src/TextUI/main.cpp
@@ -1,4 +1,4 @@
-#include "Menu.h"
+#include "../Core/Menu.h"
 #include "../Pieces/Generator.h"
 #include "../Pieces/PiecesFiles.h"
 
@@ -24,6 +24,8 @@ int main(int argc, char** argv) {
     Game game = menu.startGame(SPRINT);
     game.start();
 
+    loadFromFilesForOneSize(13);
+
     return 0;
 }
 
diff --git a/xmake.lua b/xmake.lua
index d858933..0f205d8 100644
--- a/xmake.lua
+++ b/xmake.lua
@@ -5,6 +5,7 @@ target("main")
     set_rundir(".")
     add_files("./src/Pieces/*.cpp")
     add_files("./src/Core/*.cpp")
+    add_files("./src/TextUI/*.cpp")
     set_optimize("fastest")