There is another shape similar to the long diamond that works much the same way. In this diagram, again Blue would like to prevent Red from connecting the two fences, and again he will fail.
In the second board to the right, Red has extended up from the right fence. This offers the two paths shown in hashed posts and fences. As with the long diamond, Blue can only block one of the two paths, and whichever one Blue doesn’t block, Red can take on his next move.
This connection is called the Square Diamond, because it is a square (on an angle). Where the long diamond encloses three intersections, the square diamond encloses four. If Blue had played on any of those four, the square diamond would have worked as well. The square diamond allows you to jump the diagonal of a 1×3 rectangle in any direction.
As before, Red cannot control which path Blue chooses to block. If Blue chooses to block the lower path, as in the previous example Red can choose to connect via the upper path at the cost of Blue establishing territory, or make territory himself and let Blue escape.