diff --git a/src/Acceleration.java b/src/Acceleration.java
index 8a8aef6..5a9ae7e 100644
--- a/src/Acceleration.java
+++ b/src/Acceleration.java
@@ -1,37 +1,41 @@
 import java.util.*;
 
 public class Acceleration {
-	private Map.Entry<Double, Double> force;
-	private double mass;
-	private Velocity velocity;
-	private Onground onground;
-	private Map.Entry<Double, Double> acceleration;
-	public void updateForce(Map.Entry<Double, Double> force) {
-		this.force = force;
-		Map.Entry<Double, Double> temp_l3;
-		if(this.onground.getOnground()) {
-			temp_l3 = new AbstractMap.SimpleEntry<>((force.getKey()/mass), 0.0);
-		} else {
-			temp_l3 = new AbstractMap.SimpleEntry<>((force.getKey()/mass), (force.getValue()/mass));
-		}
-		acceleration = temp_l3;
-		velocity.updateAcceleration(acceleration);
-	}
-	public void updateMass(double mass) {
-		this.mass = mass;
-		Map.Entry<Double, Double> temp_l6;
-		if(this.onground.getOnground()) {
-			temp_l6 = new AbstractMap.SimpleEntry<>((force.getKey()/mass), 0.0);
-		} else {
-			temp_l6 = new AbstractMap.SimpleEntry<>((force.getKey()/mass), (force.getValue()/mass));
-		}
-		acceleration = temp_l6;
-		velocity.updateAcceleration(acceleration);
-	}
-	public Acceleration(Velocity velocity, Onground onground) {
-		this.onground = onground;
-	}
-	public Map.Entry<Double, Double> getAcceleration() {
-		return acceleration;
-	}
+    private Pair<Double> force;
+    private double mass;
+    private Velocity velocity;
+    private Onground onground;
+    private Pair<Double> value;
+
+    public void updateForce(Pair<Double> force) {
+        this.force = force;
+        Pari<Double> temp_l3;
+        if (this.onground.getOnground()) {
+            temp_l3 = new Pair<>((force.getFirst() / mass), 0.0);
+        } else {
+            temp_l3 = new Pair<>((force.getFirst() / mass), (force.getSecond() / mass));
+        }
+        value = temp_l3;
+        velocity.updateAcceleration(value);
+    }
+
+    public void updateMass(double mass) {
+        this.mass = mass;
+        Pair<Double> temp_l6;
+        if (this.onground.getOnground()) {
+            temp_l6 = new Pair<>((force.getFirst() / mass), 0.0);
+        } else {
+            temp_l6 = new Pair<>((force.getFirst() / mass), (force.getSecond() / mass));
+        }
+        value = temp_l6;
+        velocity.updateAcceleration(value);
+    }
+
+    public Acceleration(Velocity velocity, Onground onground) {
+        this.onground = onground;
+    }
+
+    public Pair<Double> getValue() {
+        return value;
+    }
 }
\ No newline at end of file
diff --git a/src/Clear.java b/src/Clear.java
index 336e723..f60d398 100644
--- a/src/Clear.java
+++ b/src/Clear.java
@@ -7,7 +7,7 @@
 	}
 	public boolean getClear() {
 		boolean temp_l1;
-		if((this.position.getPosition().getKey()>100.0)) {
+		if((this.position.getPosition().getFirst()>100.0)) {
 			temp_l1 = true;
 		} else {
 			temp_l1 = false;
diff --git a/src/Force.java b/src/Force.java
index e379404..ac7c47f 100644
--- a/src/Force.java
+++ b/src/Force.java
@@ -2,15 +2,15 @@
 
 public class Force {
 	private Acceleration acceleration;
-	private Map.Entry<Double, Double> force;
+	private Pair<Double> value;
 	public Force(Acceleration acceleration) {
 		this.acceleration = acceleration;
 	}
 	public void gravity(double y) {
-		this.force = new AbstractMap.SimpleEntry<>(0.0, y);
-		acceleration.updateForce(force);
+		this.value = new Pair<>(0.0, y);
+		acceleration.updateForce(value);
 	}
-	public Map.Entry<Double, Double> getForce() {
-		return force;
+	public Pair<Double> getValue() {
+		return value;
 	}
 }
\ No newline at end of file
diff --git a/src/Gameover.java b/src/Gameover.java
index 5f17032..5069af2 100644
--- a/src/Gameover.java
+++ b/src/Gameover.java
@@ -7,7 +7,7 @@
 	}
 	public boolean getGameover() {
 		boolean temp_l5;
-		if((this.position.getPosition().getValue()<-(1.0))) {
+		if((this.position.getPosition().getSecond()<-(1.0))) {
 			temp_l5 = true;
 		} else {
 			temp_l5 = false;
diff --git a/src/Ground.java b/src/Ground.java
index f3dfaf8..249ad73 100644
--- a/src/Ground.java
+++ b/src/Ground.java
@@ -1,8 +1,8 @@
 import java.util.*;
 
 public class Ground {
-	private boolean ground;
-	public boolean getGround() {
-		return ground;
+	private boolean value;
+	public boolean getValue() {
+		return value;
 	}
 }
\ No newline at end of file
diff --git a/src/JumpGame.java b/src/JumpGame.java
index 8684695..ffc6f34 100644
--- a/src/JumpGame.java
+++ b/src/JumpGame.java
@@ -25,10 +25,10 @@
 	public void setMass(double x) {
 		this.mass.setMass(x);
 	}
-	public Map.Entry<Double, Double> getAcceleration() {
+	public Pair<Double> getAcceleration() {
 		return acceleration.getAcceleration();
 	}
-	public Map.Entry<Double, Double> getMove() {
+	public Pair<Double> getMove() {
 		return move.getMove();
 	}
 	public double getMass() {
@@ -40,13 +40,13 @@
 	public boolean getGround() {
 		return ground.getGround();
 	}
-	public Map.Entry<Double, Double> getForce() {
+	public Pair<Double> getForce() {
 		return force.getForce();
 	}
-	public Map.Entry<Double, Double> getVelocity() {
+	public Pair<Double> getVelocity() {
 		return velocity.getVelocity();
 	}
-	public Map.Entry<Double, Double> getPosition() {
+	public Pair<Double> getPosition() {
 		return position.getPosition();
 	}
 	public boolean getOnground() {
diff --git a/src/Mass.java b/src/Mass.java
index c381628..e98938a 100644
--- a/src/Mass.java
+++ b/src/Mass.java
@@ -2,15 +2,15 @@
 
 public class Mass {
 	private Acceleration acceleration;
-	private double mass;
+	private double value;
 	public Mass(Acceleration acceleration) {
 		this.acceleration = acceleration;
 	}
-	public void setMass(double x) {
-		this.mass = x;
-		acceleration.updateMass(mass);
+	public void setValue(double x) {
+		this.value = x;
+		acceleration.updateMass(value);
 	}
-	public double getMass() {
-		return mass;
+	public double getValue() {
+		return value;
 	}
 }
\ No newline at end of file
diff --git a/src/Move.java b/src/Move.java
index 5f99f99..0d18dbe 100644
--- a/src/Move.java
+++ b/src/Move.java
@@ -2,18 +2,18 @@
 
 public class Move {
 	private Velocity velocity;
-	private Map.Entry<Double, Double> move;
+	private Pair<Double> value;
 	public Move(Velocity velocity) {
 		this.velocity = velocity;
 	}
 	public void moveX(double x) {
-		this.move = new AbstractMap.SimpleEntry<>(x, this.move.getValue());
-		velocity.updateMove(move);
+		this.value = new Pair<>(x, this.value.getSecond());
+		velocity.updateMove(value);
 	}
 	public void moveY(double y) {
-		this.move = new AbstractMap.SimpleEntry<>(this.move.getKey(), y);
+		this.value = new Pair<>(this.value.getFirst(), y);
 	}
-	public Map.Entry<Double, Double> getMove() {
-		return move;
+	public Pair<Double> getValue() {
+		return value;
 	}
 }
\ No newline at end of file
diff --git a/src/Onground.java b/src/Onground.java
index 694d757..8ba9c2b 100644
--- a/src/Onground.java
+++ b/src/Onground.java
@@ -8,6 +8,6 @@
 		this.position = position;
 	}
 	public boolean getOnground() {
-		return ((this.ground.getGround()==true)&&(this.position.getPosition().getValue()<=0.0));
+		return ((this.ground.getGround()==true)&&(this.position.getPosition().getSecond()<=0.0));
 	}
 }
\ No newline at end of file
diff --git a/src/Pair.java b/src/Pair.java
new file mode 100644
index 0000000..4c24770
--- /dev/null
+++ b/src/Pair.java
@@ -0,0 +1,19 @@
+import java.util.*;
+
+public class Pair<T> {
+    private T first;
+    private T second;
+
+    public Pair(T first, T second) {
+        this.first = first;
+        this.second = second;
+    }
+
+    public T getFirst() {
+        return this.first;
+    }
+
+    public T getSecond() {
+        return this.second;
+    }
+}
diff --git a/src/Position.java b/src/Position.java
index e69ad66..e132696 100644
--- a/src/Position.java
+++ b/src/Position.java
@@ -2,20 +2,20 @@
 
 public class Position {
 	private Ground ground;
-	private Map.Entry<Double, Double> position;
-	public void updateVelocity(Map.Entry<Double, Double> velocity) {
-		Map.Entry<Double, Double> temp_l4;
-		if(((this.ground.getGround()==true)&&((this.position.getValue()+(0.01*velocity.getValue()))<0.0))) {
-			temp_l4 = new AbstractMap.SimpleEntry<>((this.position.getKey()+(0.01*velocity.getKey())), 0.0);
+	private Pair<Double> value;
+	public void updateVelocity(Pair<Double> velocity) {
+		Pair<Double> temp_l4;
+		if(((this.ground.getGround()==true)&&((this.value.getSecond()+(0.01*velocity.getSecond()))<0.0))) {
+			temp_l4 = new Pair<>((this.value.getFirst()+(0.01*velocity.getFirst())), 0.0);
 		} else {
-			temp_l4 = new AbstractMap.SimpleEntry<>((this.position.getKey()+(0.01*velocity.getKey())), (this.position.getValue()+(0.01*velocity.getValue())));
+			temp_l4 = new Pair<>((this.value.getFirst()+(0.01*velocity.getFirst())), (this.value.getSecond()+(0.01*velocity.getSecond())));
 		}
-		position = temp_l4;
+		value = temp_l4;
 	}
 	public Position(Ground ground) {
 		this.ground = ground;
 	}
-	public Map.Entry<Double, Double> getPosition() {
-		return position;
+	public Pair<Double> getValue() {
+		return value;
 	}
 }
\ No newline at end of file
diff --git a/src/Time.java b/src/Time.java
index cf5540a..ec23892 100644
--- a/src/Time.java
+++ b/src/Time.java
@@ -1,11 +1,11 @@
 import java.util.*;
 
 public class Time {
-	private double time;
+	private double value;
 	public void gravity(double y) {
-		this.time = (this.time+0.01);
+		this.value = (this.value +0.01);
 	}
-	public double getTime() {
-		return time;
+	public double getValue() {
+		return value;
 	}
 }
\ No newline at end of file
diff --git a/src/Velocity.java b/src/Velocity.java
index 5522079..89bb343 100644
--- a/src/Velocity.java
+++ b/src/Velocity.java
@@ -1,37 +1,37 @@
 import java.util.*;
 
 public class Velocity {
-	private Map.Entry<Double, Double> move;
-	private Map.Entry<Double, Double> acceleration;
+	private Pair<Double> move;
+	private Pair<Double> acceleration;
 	private Position position;
 	private Onground onground;
-	private Map.Entry<Double, Double> velocity;
-	public void updateMove(Map.Entry<Double, Double> move) {
+	private Pair<Double> value;
+	public void updateMove(Pair<Double> move) {
 		this.move = move;
-		Map.Entry<Double, Double> temp_l0;
-		if((this.onground.getOnground()&&(move.getValue()>=0.0))) {
+		Pair<Double> temp_l0;
+		if((this.onground.getOnground()&&(move.getSecond()>=0.0))) {
 			temp_l0 = move;
 		} else {
-			temp_l0 = this.velocity;
+			temp_l0 = this.value;
 		}
-		velocity = temp_l0;
-		position.updateVelocity(velocity);
+		value = temp_l0;
+		position.updateVelocity(value);
 	}
-	public void updateAcceleration(Map.Entry<Double, Double> acceleration) {
+	public void updateAcceleration(Pair<Double> acceleration) {
 		this.acceleration = acceleration;
-		Map.Entry<Double, Double> temp_l2;
-		if((this.onground.getOnground()&&(this.velocity.getValue()<0.0))) {
-			temp_l2 = new AbstractMap.SimpleEntry<>((this.velocity.getKey()+(0.01*acceleration.getKey())), 0.0);
+		Pair<Double> temp_l2;
+		if((this.onground.getOnground()&&(this.value.getSecond()<0.0))) {
+			temp_l2 = new Pair<>((this.value.getFirst()+(0.01*acceleration.getFirst())), 0.0);
 		} else {
-			temp_l2 = new AbstractMap.SimpleEntry<>((this.velocity.getKey()+(0.01*acceleration.getKey())), (this.velocity.getValue()+(0.01*acceleration.getValue())));
+			temp_l2 = new Pair<>((this.value.getFirst()+(0.01*acceleration.getFirst())), (this.value.getSecond()+(0.01*acceleration.getSecond())));
 		}
-		velocity = temp_l2;
-		position.updateVelocity(velocity);
+		value = temp_l2;
+		position.updateVelocity(value);
 	}
 	public Velocity(Position position, Onground onground) {
 		this.onground = onground;
 	}
-	public Map.Entry<Double, Double> getVelocity() {
-		return velocity;
+	public Pair<Double> getValue() {
+		return value;
 	}
 }
\ No newline at end of file