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Hydra (922)
Instruction:
Locate a "hydra" in the grid. The hydra is a region of orthogonally-connected cells. The hydra cannot go through any cells marked with '×'. No 2×2 group of cells can be entirely shaded black, and all cells that are not part of the hydra must be connected orthogonally (through other non-hydra cells) to the edge of the grid (in other words, the hydra may not loop or touch itself diagonally). All hydra cells that touch only one other hydra cell are provided. One of them is the "tail" of the hydra and labeled with the number 1; the others are the "heads" of the hydra and each one is labeled with the number of hydra cells that are needed to connect the tail of the hydra with that head (including the head and tail cells).