Help with model of Hexagonal Close Packed Crystal Structure

unhandled

#1

Hi everybody,

I am trying to draw Hexagonal Close Packed Crystal Structure just for fun. The spheres “A” are not problem, unfortunately I don’t know, how to draw the spheres “B” that they touch spheres “A” without gaps or overlapping. Has somebody a good advice?
https://www.e-education.psu.edu/matse81/node/2134