We don't need to worry about the other sides (above, left) because those nodes don't exist.
What are we looking to do? We need to visit every neighbor, and then every one of its neighbors. This sounds like a graph traversal problem.
How many times do we need to perform a node operation? As long as there are nodes that match the initial one that we clicked on or started at.
Knowing this, we could go with either go with a Breadth-first search or a Depth-first search approach.
