TBR phase changes

[sillyjoe]

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In Section 7 of Physics TBR they discuss unit cells and show pictures in Figure 7-1 of how many atoms there are per unit cell for simple cubic and face-centered cubic.

Can someone please explain to me how this picture shows one atom per cell and four atoms per cell respectively? I don't see what they are counting to reach that number?

 

[SweetBurger]

If you look at the picture for a simple cubic cell it has exactly 1 atom in it, but its broken up into 8th's. If you were to add up all the shapes inside the simple cubic cell it would come out to be 1 atom.
Now for the face centered cubic cell i will add an image, because I think the TBR's pic is a bit hard to interpret. Now if you were to add up all the shapes it would come out to be 4 atoms.