is played on a grid of irregular shape. Some cells of the grid contain 'X' and 'O'. The task is to fill in the grid so that four consecutive identical symbols never appear in any row, column or diagonal. ============KEYWORDS/TAGS: logic puzzle books for kids - easy logic puzzles - logic puzzle 12 year old - brain teasers for kids ages 10-12 - brain teasers for teens - brain teasers for kids - brain teaser for teens - brain teaser games for teens - brain teaser games for kids - brain teaser kids - brain teaser puzzles for teens - brain teaser puzzles for kids - brain teaser 12 year old - logic puzzle books for teens