Mosco
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A puzzle taken from Ivan Moscovich's "Magic Arrow Tile
Puzzles".  Given a grid, fill it with arrows so that
the clues around the edges match the number of arrows
pointing at them.  There are a limited number of each
"type" of arrow (up, down, up-left, etc.) depending on
the size of the grid.

A-Click to change the arrow in a square.
B-Click on the outside edges of a square to insert a 
"guess" arrow to help you solve the puzzle.
Y-Click to clear a square of all arrows.
