3girls, ahoge, artist_name, from_behind, from_side, graphite_(medium), greyscale, hair_ribbon, horizon, long_hair, looking_at_another, looking_to_the_side, monochrome, multiple_girls, ocean, open_mouth, outdoors, outstretched_arm, partially_submerged, pointing, pointing_up, ponytail, ribbon, scenery, signature, sketch, sky, traditional_media, tri_tails, two_side_up, waves