One Tip a Day

Today, we'll clear squares by satisfying both the 'one cat per row and column' rule and the 'one cat per color' rule together. 1. The blue square box has two horizontal rows, and the colors filled within are yellow and pink, making two colors. 2. With two rows and two colors, there's exactly one cat per row, right? 3. Then, any yellow or pink squares outside of the two rows within the square box must not have cats, so we mark them with an X. In the same way, if three rows are filled with three colors, or four rows with four colors, you can erase squares of other colors or those outside the designated area.