jMol series twin planes

Here's a spherical silicon nanosphere with a single {111} twin plane. It divides two lattices which are rotated 180 degrees from one another about that plane. What's different structurally on opposite sides of the highlighted plane?
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Below to the left find a comparison between an experimental high-res electron microscope image (top: green) of a "nanotwin end" in germanium, and a simulated image (bottom: grey) of the jmol model above. Any ideas how to explain the difference?

Here is a darkfield image of a pair of <111> nanotwins found in gigascale integrated circuit silicon as manufacturers were working to scale up to the routine production of 12 inch diameter wafers.

Below find comparison between that experimental Ge image and a physical model put together by Danielle K for a Science Fair project.