Nunnally writes something in a notebook. From this distance, Lelouch can't make out the sound of pencil scratching paper. Nunnally places a ribbon as a bookmark on the page and smiles. At this point in time, Nunnally still can't smile at exactly the right angle. It looks like Nunnally is smiling to someone just to Lelouch's left.
Lelouch declines coming over, preferring to watch from the top of the hill. From here, Lelouch can see all the butterflies in the meadow. They are a deep velvet blue, and when they flap their wings in unison it almost looks like a mysterious rite brought them all here, at once. Maybe to coronate Nunnally in some long forgotten, alternative Emperor way.
This meadow was the sanctuary of the garden keepers at court. The other siblings use this time to duel or spy on the townspeople. Nunnally can't do either. So they come here, to a place only a few servants remember, a place out of the minds of the rest of the royal family.
The garden keepers did their job beautifully. Butterfly bushes sprout without care in the bowl of the valley. Thanks to strategically planted oak trees on the hill, there's just enough shade to prevent overdosing the bushes with sun.
As for the butterflies… who knows why these ones, with their stunning and three dimensional colors, decide to roam here? An exotic far away species, but they congregate every day… Frolicking around Nunnally, pausing to sniff at Nunnally's long hair, flying away and then back to the blind daughter.
Nunnally tries to stand up very slightly, more like a normal person starting to tiptoe than really standing up. Nunnally can hold this pose for about two seconds. The butterflies flap their wings more frantically.
Nunnally's notebook begins sliding off, and suddenly the sun strikes the page, and Lelouch sees with crystal clarity a vividly drawn butterfly on the page, right before the notebook falls.