Kropki
Rules
Fill in the grid with digits from 1 to 6 putting one digit per a cell. Each row and column should contain every digit exactly once. If two consecutive digits appear in two neighboring cells, they are separated by a white dot. If the digit in a cell is half of the digit in the neighboring cell, then they are marked by a black dot. The dot between 1 and 2 can either be white or be black.
Click to see the answer.