Example puzzle
This is an example puzzle. You can solve it the same way as you would solve competition puzzle, but result never stored. You can reveal an answer for the puzzle by clicking "Show answer" link.
Kropki
Author: Andrey Bogdanov
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.
Grid control: Click at a cell reveals the value chooser. Click at the selected value changes the state of the cell. More details about grid control are at the help page.