Veloviewer Tile Bagging?

Your Max Explorer Cluster is the largest set of connecting, visited Explorer Tiles which each have their four immediate neighbouring tiles (above, below, left & right) also visited. In the above image, taken from my own Activities page, you can see all of the visited explorer tiles coloured in red & blue. The blue tiles are showing my Max Explorer Cluster. Each one of those blue tiles has a visited tile (i.e. red or blue) immediately above and to the side. As you can see near the top left corner, missing a single tile results in a hole of 5 tiles in the cluster. The idea is obviously to make the biggest cluster you can!

A max square is the largest square that fits in your cluster. It gets exponentially harder to grow a square as you need more and more tiles to expand it by 1.