Put three check marks in every row and every column. Check marks may not be placed next to or above each other. Tip: put a cross on the positions that may not contain a check mark. check marks puzzle,logic puzzle,mind games,spatial reasoning,brain teaser,puzzle game,critical thinking,concentration,problem solving,logic skills,mindful puzzles,grid puzzle,brain exercise,interactive puzzle,check mark placement,logic challenge,brain training,mental workout,puzzle,logic game