For now, I'll do what I've done before, and slavishly copy from the WPC instructions. Enjoy!
Rules: (as taken from the WPC instructions)
Draw a single closed loop, going along the gridlines. The loop cannot touch or cross itself. The area enclosed by the loop represents a cave. All numbers inside the grid must be inside the cave. A number in a grid cell indicates how many cells (including the cell with that number) can be seen from that cell to the nearest wall in four directions, horizontally and vertically.
N.B. For anyone who hasn't solved these before, don't treat this as your average loop puzzle. Shading in squares which are either inside or outside (but not both!) is how you will solve these puzzles. In this respect I'd argue corral has more in common with nurikabe and heyawake than, say, slitherlink or masyu.
#221 Cave a.k.a. Corral – rated mediumAll puzzles © Tom Collyer 2009-12.