To emulate Minesweeper's not-a-bomb-on-the-first-click experience, I start the board off with a generous region revealed, and then to emulate flood-filling, I make blank cells sit in an invisible (overflow hidden) scroll box that scrolls to a revealed version of the region when you click the blank cells, which have relative links. That only works for rectangular regions, but I remember having a way to make it work with irregularly shaped regions and being too lazy to implement it because it was going to be even trickier and uglier than what I was already doing. I'll leave that as an exercise for the reader. :P