What they're saying is they want a lookout and a hideaway. Scale is negotiable. The paths can be made of stones, bark mulch, newspaper covered with straw, or even boards. Kids plant something different in each square. The design is tidy and manageable.
Circular gardens are fun, too.
Slice them, pie-fashion, with the paths. Once you have your basic shape, sketch it out on graph paper with one square equaling one foot. Choose the plants last. Look up and down. Before you dig, be aware of any power lines, pipes, septic systems, or other existing limitations.