diff --git a/12-shading.html b/12-shading.html
index 34d1b1f..a3c7356 100644
--- a/12-shading.html
+++ b/12-shading.html
@@ -145,7 +145,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
@@ -155,7 +155,7 @@ <h3>
           <div id="title"> code09.html COMMENTS</div>
         </h3>
         <h5>
-           A simple 3D rendering of cube using gl elemenntary array
+           A simple 3D rendering of cube using gl element array
 	  </h5> 
   </div>
 
diff --git a/12-shading.js b/12-shading.js
index 200f22f..9197f10 100644
--- a/12-shading.js
+++ b/12-shading.js
@@ -263,7 +263,7 @@ function initSQBuffers() {
         gl.vertexAttribPointer(shaderProgram.vertexColorAttribute,cylinderVertexColorBuffer.itemSize, gl.FLOAT, false, 0, 0);
 	
 
-	// draw elementary arrays - triangle indices 
+	// draw element arrays - triangle indices 
 	//  gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, squareVertexIndexBuffer);
 
 	gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, cylinderVertexIndexBuffer); 	
diff --git a/3Dcube.html b/3Dcube.html
index 3d4bbe2..11db61d 100644
--- a/3Dcube.html
+++ b/3Dcube.html
@@ -64,7 +64,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
@@ -74,7 +74,7 @@ <h3>
           <div id="title"> 3Dcube.html COMMENTS</div>
         </h3>
         <h5>
-           A simple 3D rendering of cube using gl elemenntary array. Left click mouse button and drag to rotate. 
+           A simple 3D rendering of cube using gl element array. Left click mouse button and drag to rotate. 
 	  </h5> 
   </div>
 
diff --git a/3Dcube.js b/3Dcube.js
index 9edfada..f84bde6 100644
--- a/3Dcube.js
+++ b/3Dcube.js
@@ -119,7 +119,7 @@ var draw_type=2;
         gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexColorBuffer);
         gl.vertexAttribPointer(shaderProgram.vertexColorAttribute,squareVertexColorBuffer.itemSize, gl.FLOAT, false, 0, 0);
 
-	// draw elementary arrays - triangle indices 
+	// draw element arrays - triangle indices 
         gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, squareVertexIndexBuffer); 
 
        setMatrixUniforms();   // pass the modelview mattrix and projection matrix to the shader 
diff --git a/8-transform-ortho2D.html b/8-transform-ortho2D.html
index c16b7f4..012a17a 100644
--- a/8-transform-ortho2D.html
+++ b/8-transform-ortho2D.html
@@ -64,7 +64,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/Mtransforms.html b/Mtransforms.html
index 91d593b..226cec9 100644
--- a/Mtransforms.html
+++ b/Mtransforms.html
@@ -67,7 +67,7 @@ <h4> Background:  </h4>
 
 
     <h4>
-      - Click on the left mouse button and move the coursor to rotate; select the squre and apply 'X', 'x', 'Y','y' 
+      - Click on the left mouse button and move the cursor to rotate; select the squre and apply 'X', 'x', 'Y','y' 
     </h4>
 
     </h4>
diff --git a/color-triangles.js b/color-triangles.js
index d933089..e3d116d 100644
--- a/color-triangles.js
+++ b/color-triangles.js
@@ -68,7 +68,7 @@
         gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, squareVertexPositionBuffer.itemSize, gl.FLOAT, false, stride, offset);
 
         gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexColorBuffer);
-        gl.vertexAttribPointer(shaderProgram.vertexColorAttribute, squareVertexColorBuffer.itemSize, gl.FLOAT, false, offset, stride);
+        gl.vertexAttribPointer(shaderProgram.vertexColorAttribute, squareVertexColorBuffer.itemSize, gl.FLOAT, false, stride, offset);
 
         gl.drawArrays(gl.TRIANGLE_STRIP, offset, squareVertexPositionBuffer.numItems);
 
diff --git a/cubeMappedTeapot.html b/cubeMappedTeapot.html
index dfe4a75..9991be1 100644
--- a/cubeMappedTeapot.html
+++ b/cubeMappedTeapot.html
@@ -183,7 +183,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
@@ -193,7 +193,7 @@ <h3>
           <div id="title"> cubeMappedTeapot.html </div>
         </h3>
         <h5>
-           An exmple of rendering Utah teapot using Environment Cube Map
+           An example of rendering Utah teapot using Environment Cube Map
 	  </h5> 
   </div>
 
diff --git a/element-array.js b/element-array.js
index e92bd22..34b8650 100644
--- a/element-array.js
+++ b/element-array.js
@@ -75,7 +75,7 @@
         gl.vertexAttribPointer(shaderProgram.vertexColorAttribute, squareVertexBuffer.numFloats, gl.FLOAT, false,stride, offset); // 6*4 is the stride size, 3*4 is the offset 
         offset = 0; 
 
-        // draw elementary arrays - triangle indices 
+        // draw element arrays - triangle indices 
         gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, squareVertexIndexBuffer); 
         gl.drawElements(gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0); 
 
diff --git a/hierarchicalXform.html b/hierarchicalXform.html
index 416eb5e..906b9b5 100644
--- a/hierarchicalXform.html
+++ b/hierarchicalXform.html
@@ -67,7 +67,7 @@ <h4> Background:  </h4>
 
 
     <h4>
-      - Click on the left mouse button and move the coursor to rotate. select square 1, 2, 3 and apply 'X, 'x', 'Y', 'y'
+      - Click on the left mouse button and move the cursor to rotate. select square 1, 2, 3 and apply 'X, 'x', 'Y', 'y'
     </h4>
 
     </h4>
diff --git a/shading.html b/shading.html
index 53ad796..ecc25d1 100644
--- a/shading.html
+++ b/shading.html
@@ -145,7 +145,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/shading.js b/shading.js
index 200f22f..9197f10 100644
--- a/shading.js
+++ b/shading.js
@@ -263,7 +263,7 @@ function initSQBuffers() {
         gl.vertexAttribPointer(shaderProgram.vertexColorAttribute,cylinderVertexColorBuffer.itemSize, gl.FLOAT, false, 0, 0);
 	
 
-	// draw elementary arrays - triangle indices 
+	// draw element arrays - triangle indices 
 	//  gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, squareVertexIndexBuffer);
 
 	gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, cylinderVertexIndexBuffer); 	
diff --git a/simple-transform.html b/simple-transform.html
index 0df1ef6..4cf8025 100644
--- a/simple-transform.html
+++ b/simple-transform.html
@@ -64,7 +64,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/teapot.html b/teapot.html
index 95cd2df..d65d3b4 100644
--- a/teapot.html
+++ b/teapot.html
@@ -140,7 +140,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/teapotFBO.html b/teapotFBO.html
index 13835ac..daba167 100644
--- a/teapotFBO.html
+++ b/teapotFBO.html
@@ -175,7 +175,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
@@ -185,7 +185,7 @@ <h3>
           <div id="title"> teapotFBO.html</div>
         </h3>
         <h5>
-           An exmple of using Frame Buffer Object (FBO)
+           An example of using Frame Buffer Object (FBO)
 	  </h5> 
   </div>
 
diff --git a/texture.html b/texture.html
index 30a9ebb..7b882d3 100644
--- a/texture.html
+++ b/texture.html
@@ -168,7 +168,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
@@ -178,7 +178,7 @@ <h3>
           <div id="title"> code10.html COMMENTS</div>
         </h3>
         <h5>
-           A simple 3D rendering of cube using gl elemenntary array
+           A simple 3D rendering of cube using gl element array
 	  </h5> 
   </div>
 
diff --git a/texture.js b/texture.js
index 9064863..e4cf0ca 100644
--- a/texture.js
+++ b/texture.js
@@ -198,7 +198,7 @@ function initSQBuffers() {
         gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexColorBuffer);
         gl.vertexAttribPointer(shaderProgram.vertexColorAttribute,squareVertexColorBuffer.itemSize, gl.FLOAT, false, 0, 0);
 
-	// draw elementary arrays - triangle indices 
+	// draw element arrays - triangle indices 
         gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, squareVertexIndexBuffer);
 
 	setMatrixUniforms();   // pass the modelview mattrix and projection matrix to the shader 
diff --git a/textureTeapot.html b/textureTeapot.html
index d0e66d6..e5fe8b3 100644
--- a/textureTeapot.html
+++ b/textureTeapot.html
@@ -168,7 +168,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/uniform-color-xform.html b/uniform-color-xform.html
index 8d583c5..b3a1529 100644
--- a/uniform-color-xform.html
+++ b/uniform-color-xform.html
@@ -58,7 +58,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/xform.html b/xform.html
index 0334aa2..667734d 100644
--- a/xform.html
+++ b/xform.html
@@ -58,7 +58,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/xform.js b/xform.js
index ce720cc..9d2f523 100644
--- a/xform.js
+++ b/xform.js
@@ -223,7 +223,8 @@ function BG(red, green, blue) {
 } 
 
 function redraw() {
-    Z_angle = 0; 
+    Z_angle = 0;
+    z_angle = 0;
     drawScene();
 }
     
diff --git a/xform2.html b/xform2.html
index 71c0889..91919ed 100644
--- a/xform2.html
+++ b/xform2.html
@@ -58,7 +58,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/xform2.js b/xform2.js
index 29073b8..ab3b8fd 100644
--- a/xform2.js
+++ b/xform2.js
@@ -220,6 +220,9 @@ function BG(red, green, blue) {
 } 
 
 function redraw() {
+    mat4.identity(mvMatrix);
+    mvMatrix = mat4.translate(mvMatrix, [-0.5, 0, 0]); 
+    mvMatrix = mat4.scale(mvMatrix, [0.2, 0.2, 0.2]); 
     drawScene();
 }
     
diff --git a/xform3.html b/xform3.html
index dd861e3..65971b2 100644
--- a/xform3.html
+++ b/xform3.html
@@ -59,7 +59,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/xform3.js b/xform3.js
index cc064e6..a0c1748 100644
--- a/xform3.js
+++ b/xform3.js
@@ -245,6 +245,11 @@ function BG(red, green, blue) {
 } 
 
 function redraw() {
+    degree2 = 0;
+    degree3 = 0;
+    mat4.identity(mvMatrix);
+    mvMatrix = mat4.translate(mvMatrix, [-0.5, 0, 0]); 
+    mvMatrix = mat4.scale(mvMatrix, [0.2, 0.2, 0.2]); 
     drawScene();
 }
     
diff --git a/xform4.html b/xform4.html
index 9f6abbe..59d1313 100644
--- a/xform4.html
+++ b/xform4.html
@@ -59,7 +59,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/xform4.js b/xform4.js
index 91ee752..3b58ff5 100644
--- a/xform4.js
+++ b/xform4.js
@@ -262,6 +262,11 @@ function BG(red, green, blue) {
 } 
 
 function redraw() {
+    degree2 = 0;
+    degree3 = 0;
+    mat4.identity(mvMatrix);
+    mvMatrix = mat4.translate(mvMatrix, [-0.5, 0, 0]); 
+    mvMatrix = mat4.scale(mvMatrix, [0.2, 0.2, 0.2]);
     drawScene();
 }
     
diff --git a/xform5.html b/xform5.html
index 0bf1eb4..fb0fe6b 100644
--- a/xform5.html
+++ b/xform5.html
@@ -59,7 +59,7 @@ <h4> Background:  </h4>
 
     <div>
     <h4>
-    Click on the left mouse button and move the coursor to rotate
+    Click on the left mouse button and move the cursor to rotate
     </h4>
     <button  onclick="redraw()"> Go Back! </button>
     </div>
diff --git a/xform5.js b/xform5.js
index 2a22def..50e5853 100644
--- a/xform5.js
+++ b/xform5.js
@@ -289,6 +289,11 @@ function BG(red, green, blue) {
 } 
 
 function redraw() {
+    mat4.identity(mvMatrix);
+    mvMatrix = mat4.translate(mvMatrix, [-0.5, 0, 0]); 
+    mvMatrix = mat4.scale(mvMatrix, [0.2, 0.2, 0.2]); 
+    degree2 = 0;
+    degree3 = 0;
     drawScene();
 }