Why does FCC crystalline forms form hexagonal crystalline structures during CVD?

During the CVD process, Copper and Nickel which are both Face Centered Cubic crystalline structures are used as substrates for shaping hexagonal atomic structures such as graphene and hexagonal Boron-Nitride. Why is it that these form hexagonal atomic structures when they themselves aren't hexagonal?





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> [Ivan Neretin] But they are hexagonal, if you look at them sideways. – 
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> [OP] Sorry I dont quite grasp what you mean. Do you have a visual representation?
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Here is the [visual](http://lampx.tugraz.at/%7Ehadley/ss1/crystalstructure/structures/fcc/fcc_jsmol.php).


[![enter image description here](https://i.stack.imgur.com/KJcBk.gif)](https://i.stack.imgur.com/KJcBk.gif)



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> [Jon Custer] Fcc and hcp structures are similar stacking (fcc you need to look along the 111 body diagonal - a classic issue with the cubic conventional cell).
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Yes, both may be constructed by stacking hexagonal layers, either in an ABABA.. (hexagonal close packing hcp) or an ABCABCA.. (face-centered cubic fcc) fashion.


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