Minecraft wiki entry for Village_chaining, associated text: 3. To prevent itself from being unnecessarily long or wide, figures in this section use planks and fences to represent valid door positions and village radius, respectively. Side-view log represents a village center that contains a valid door, while top-view log represents a door-less center. The barrier icons just represent unimportant things. More important icons may overlay less important ones. The minimum village radius in those figures is 5 blocks and the merging range is radius + 5 blocks instead of 32 blocks and radius + 32 blocks like the real game.