These remind me of mandalas. We could get stones and do mandala zendoodle art on them, and then write a simple encouraging message on the back for baby girl. Make a nice fabric bag for her to keep them in.
This could be good for the gazebo or somewhere else like the front porch if the diagonal hammock is too invasive. It could also be cute to have two hammocks on the front porch on either end of the rocking chairs which would create a cozy perimeter.