SEKI
Using the blank grid, rotate some of the circles shown in the start grid and then shade in the corresponding squares (as shown above), so that each black quarter-circle is within a shaded square and white one in a blank square.
Using the blank grid, rotate some of the circles shown in the start grid and then shade in the corresponding squares (as shown above), so that each black quarter-circle is within a shaded square and white one in a blank square.