George and maria decided to create a garden in their backyard. george works on the garden every third day and maria works on the garden every fourth day. if they worked on the garden today, the number of days until they work on the same day again would be

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.