Island Sea· Advanced

Goal

Fill all empty cells as either island (white) or sea (black) to complete the puzzle.

Rules

  • Numbers indicate the size of their island (count of connected white cells)
  • Each island contains exactly one number
  • Different islands cannot be orthogonally adjacent
  • All sea (black) cells must form one connected group
  • Sea cells cannot form a 2×2 square (no pools)
1
3
4

Start with cells numbered 1 — all 4 surrounding cells are sea. Since 2×2 sea blocks are forbidden, if 3 sea cells form an L-shape, the 4th must be island.

Island Sea puzzles train spatial reasoning, path connectivity analysis, and constraint satisfaction problem (CSP) solving skills. Research shows that spatial cognition puzzles improve visuospatial working memory and problem-solving abilities.

  • Uttal, D. H., et al. (2013). "The malleability of spatial skills: A meta-analysis of training studies." Psychological Bulletin, 139(2), 352-402.
  • Miyake, A., et al. (2001). "How are visuospatial working memory, executive functioning, and spatial abilities related?" J. Exp. Psychol. Gen., 130(4), 621-640.