I have the data X contains the grades of some students in 4 subjects:

       Math Phys   Fr  Ang
Benny   6.0  6.0  5.0  5.5
Bobby   8.0  8.0  8.0  8.0
Brandy  6.0  7.0 11.0  9.5
Coby   14.5 14.5 15.5 15.0
Daisy  14.0 14.0 12.0 12.5
Emily  11.0 10.0  5.5  7.0
Judy    5.5  7.0 14.0 11.5
Marty  13.0 12.5  8.5  9.5
Sandy   9.0  9.5 12.5 12.0

Then I do PCA to get the projection of this data matrix into the space spanned by two first components. Then I plot them and have a graph

To me, the graph only shows the coordinate of our original data in the principal plane. Could you please elaborate on how to interpret (or get meaningful insights) from this graph?