Create a stacked contour plot of the MRI data, showing the first, eight, and twelfth layer of the data.

An MRI visualization example is shown in the help tutorial. Copy and paste the commands into an M-file and run the example. Be sure to add the clf command before drawing each new plot.

My book did a god awful job explaining Volume visualization. I don't think it even really expects me to have that great of a understanding of it neither sense it directly tells me to just copy the code from the tutorial and add the clf command in the second part of the question. As a result of not having that great understanding of this I'm complete lost. The code in the tutorial is

load mri
D = squeeze(D);
[x,y,z,D] = reducevolume(D,[4,4,1]);
D = smooth3(D);
p1 = patch(isosurface(x,y,z,D, 5,'verbose'),...
'FaceColor','red','EdgeColor','none');
isonormals(x,y,z,D,p1);
p2 = patch(isocaps(x,y,z,D, 5),...
'FaceColor','interp','EdgeColor','none');
view(3); axis tight; daspect([1,1,.4])
colormap(gray(100))
camlight; lighting gouraud

also if you didn't know the MRI data is automatically stored in MATLAB that's why you can just load it. I'm not exactly sure how to solve the first part of the question or the second, I'm not exactly sure were I'm suppose to add the clf command to get the results the question is expecting from me. I missed around with the code and the only way I could a result different than from the original code was by adding it right after the isonormals function

for the first part of the question I originally thought I was suppose to use the countour slice function or something but that function didn't even appear in our book any were, nor do I think I have sufficient data to use it by simply loading the data stored with MATLAB... hence I'm completely lost on these questions...

This is the tutorial it's making a reference to

h t t p : / / w w w . m a t h w o r k s . c o m / h e l p / t e c h d o c / r e f / r e d u c e v o l u m e . h t m l

at least I think it is >_>