The chief cause of problems is solutions!

Concept 1.7: The order of transformations
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Idea:
=====
In OpenGL the order in which transformations are
specified have a definite effect on where the object
is rendered.  A translation followed by a rotation
leads to a much different scenario than vice versa.

Experiment:
===========
Enter values of 2, 2, -3 for Translation and values of
45, 1, 1, 0 for rotation.  Execute the code.  Now use 
the toggle switch to specify a rotation first and then
a translation in the code.  Did you see a difference?

Click on the Reset button.  Now enter (3, 0, 0) for
specifying the translation and (45, 0, 1, 0) (i.e. a 45
degree rotation about the Y axis) for the rotation.  Click
on execute.  Now use the toggle switch again. 

Question
========
Why does the order of transformations affect the final 
image?

Answer
======
Let us evaluate the input values of (3, 0, 0) for 
translation and (45, 0, 1,0) for rotation.
Initially the order is as follows :
glTranslatef(3, 0, 0);
glRotatef(45, 0, 1, 1);
drawcube();

Here a rotation about the Y axis is performed while 
still at the origin.  Next we translate the rotated cube 
about the X axis

When we use the toggle the code changes to
glRotatef(45, 0, 1, 0);
glTranslatef(3, 0, 0):
drawcube();

Here we first translate 3 units along the X axis and 
then we rotate 45 degrees along the Y axis.  This 
rotation can be viewed as travelling 45 degrees along 
a circle whose center isat the origin and radius is 3 
units along the X axis.