private static HashSet<EndPosition> PossibleEndPositions(int column, int row)
{
var possibleEndPosition = new HashSet<EndPosition>
{
new EndPosition(column + 1, row + 2),
new EndPosition(column + 1, row - 2),
new EndPosition(column - 1, row + 2),
new EndPosition(column - 1, row - 2),
new EndPosition(column + 2, row + 1),
new EndPosition(column + 2, row - 1),
new EndPosition(column - 2, row + 1),
new EndPosition(column - 2, row - 1),
};
return possibleEndPosition;
}