diff --git a/.idea/oscilloscope-experiments.iml b/.idea/oscilloscope-experiments.iml
index 2e47cbd..3d2d867 100644
--- a/.idea/oscilloscope-experiments.iml
+++ b/.idea/oscilloscope-experiments.iml
@@ -9,5 +9,15 @@
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="lib" level="project" />
+    <orderEntry type="module-library" scope="TEST">
+      <library name="JUnit4">
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/junit/junit/4.12/junit-4.12.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
   </component>
 </module>
\ No newline at end of file
diff --git a/src/AudioPlayer.java b/src/AudioPlayer.java
index c8c02bf..1414e8b 100644
--- a/src/AudioPlayer.java
+++ b/src/AudioPlayer.java
@@ -21,11 +21,11 @@ public class AudioPlayer extends Thread {
       line.rotate(nextTheta(stream.getFormat().mix.rate, 0.000001));
 
       int framesToDraw = (int) (line.length() * 100);
-      //int neg = line.getX1() < line.getX2() || line.getY1() < line.getY2() ? 1 : -1;
+      int neg = line.getX1() < line.getX2() || line.getY1() < line.getY2() ? 1 : -1;
 
       for (int c = 0; c < format.outputs; c++) {
-        ((float[]) output)[f * format.outputs] = line.getX1() + Math.abs(line.getX2() - line.getX1()) * (float) (framesDrawn) / framesToDraw;
-        ((float[]) output)[f * format.outputs + 1] = line.getY1() + Math.abs(line.getY2() - line.getY1()) * (float) (framesDrawn) / framesToDraw;
+        ((float[]) output)[f * format.outputs] = (float) (line.getX1() + Math.abs(line.getX2() - line.getX1()) * (neg * framesDrawn) / framesToDraw);
+        ((float[]) output)[f * format.outputs + 1] = (float) (line.getY1() + Math.abs(line.getY2() - line.getY1()) * (neg * framesDrawn) / framesToDraw);
       }
 
       framesDrawn++;
diff --git a/src/Line.java b/src/Line.java
index a2e19b3..1779378 100644
--- a/src/Line.java
+++ b/src/Line.java
@@ -7,20 +7,20 @@ public class Line {
     this.b = b;
   }
 
-  public Line(float x1, float y1, float x2, float y2) {
+  public Line(double x1, double y1, double x2, double y2) {
     this.a = new Point(x1, y1);
     this.b = new Point(x2, y2);
   }
 
-  public float length() {
-    return (float) Math.sqrt(Math.pow(getX1() - getX2(), 2) + Math.pow(getY1() - getY2(), 2));
+  public double length() {
+    return Math.sqrt(Math.pow(getX1() - getX2(), 2) + Math.pow(getY1() - getY2(), 2));
   }
 
   public void rotate(double theta) {
-    setX1((float) (getX1() * Math.cos(theta) - getY1() * Math.sin(theta)));
-    setY1((float) (getX1() * Math.sin(theta) + getY1() * Math.cos(theta)));
-    setX2((float) (getX2() * Math.cos(theta) - getY2() * Math.sin(theta)));
-    setY2((float) (getX2() * Math.sin(theta) + getY2() * Math.cos(theta)));
+    setX1(getX1() * Math.cos(theta) - getY1() * Math.sin(theta));
+    setY1(getX1() * Math.sin(theta) + getY1() * Math.cos(theta));
+    setX2(getX2() * Math.cos(theta) - getY2() * Math.sin(theta));
+    setY2(getX2() * Math.sin(theta) + getY2() * Math.cos(theta));
   }
 
   public Point getA() {
@@ -31,35 +31,48 @@ public class Line {
     return b;
   }
 
-  public float getX1() {
+  public double getX1() {
     return a.getX();
   }
 
-  public float getY1() {
+  public double getY1() {
     return a.getY();
   }
 
-  public float getX2() {
+  public double getX2() {
     return b.getX();
   }
 
-  public float getY2() {
+  public double getY2() {
     return b.getY();
   }
 
-  public void setX1(float x1) {
+  public void setX1(double x1) {
     a.setX(x1);
   }
 
-  public void setY1(float y1) {
+  public void setY1(double y1) {
     a.setY(y1);
   }
 
-  public void setX2(float x2) {
+  public void setX2(double x2) {
     b.setX(x2);
   }
 
-  public void setY2(float y2) {
+  public void setY2(double y2) {
     b.setY(y2);
   }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (obj == this) {
+      return true;
+    } else if (obj instanceof Line) {
+      Line line = (Line) obj;
+
+      return line.getA().equals(getA()) && line.getB().equals(getB());
+    } else {
+      return false;
+    }
+  }
 }
diff --git a/src/Point.java b/src/Point.java
index d064af9..4669fc0 100644
--- a/src/Point.java
+++ b/src/Point.java
@@ -1,25 +1,44 @@
 public class Point {
-  private float x;
-  private float y;
+  private double x;
+  private double y;
 
-  public Point(float x, float y) {
+  private static final double EPSILON = 0.0001;
+
+  public Point(double x, double y) {
     this.x = x;
     this.y = y;
   }
 
-  public float getX() {
+  public double getX() {
     return x;
   }
 
-  public float getY() {
+  public double getY() {
     return y;
   }
 
-  public void setX(float x) {
+  public void setX(double x) {
     this.x = x;
   }
 
-  public void setY(float y) {
+  public void setY(double y) {
     this.y = y;
   }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (obj == this) {
+      return true;
+    } else if (obj instanceof Point) {
+      Point point = (Point) obj;
+
+      return approxEquals(point.getX(), getX()) && approxEquals(point.getY(), getY());
+    } else {
+      return false;
+    }
+  }
+
+  private boolean approxEquals(double m, double n) {
+    return Math.abs(m - n) < EPSILON;
+  }
 }
diff --git a/test/TestSuite.java b/test/TestSuite.java
new file mode 100644
index 0000000..c3182dd
--- /dev/null
+++ b/test/TestSuite.java
@@ -0,0 +1,13 @@
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class TestSuite {
+  @Test
+  public void lineRotationTest() {
+    Line line = new Line(-0.5, 0.5, 0.5, 0.5);
+    line.rotate(Math.PI / 2);
+
+    assertEquals(new Line(0.5, 0.5, 0.5, -0.5), line);
+  }
+}
\ No newline at end of file