Edge walking in 8 connectivity

Definition: 8-connectivity
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A neighbour can be on any one of the 8 adjacent pixels (and not only on the 4
neighbours on the left/top/right/bottom)

My question is whether following observation is right?

Observation
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When walking around the edges of a white area, in 8-connectivity, then a pixel
would be repeated twice, only in the following cases:
1. It's left and right neighbours are both black
2. It's top and bottom neighbours are both black