The vital forces of nature come into play in the decorative color lithograph Reiter und Reiterin (Man and Woman Riding), and the tender eroticism which makes the couple lovers is characteristic of Erni's work.

Hans Erni is a virtuoso of the nude. The pair remained one of his leitmotifs. Human encounters with other humans, be it within the family, in sports, in the workplace or in science and art, or human encounters with the elements - water, fire, air and earth - in the exchange with the seasons and in the questioning of the cosmic powers and signs of the zodiac. Horses appear in Hans Erni's posters early on and repeatedly, for example, in his poster for the 'Concours Hippique' or for the National Swiss Circus, 'Knie'. In the original graphic works, his first lithographs from the 50's are images of horses - and to this day, the theme of the rider and the playful animal is a part of his pictorial vocabulary. This is also true of some of his sculptures, such as the Centaurs, Chiron and the Trojan Horse. Erni brought Ancient man into the present. Athena, from 1986, is an unusually touching image, in which an owl fuses with Athena's head. In 1986, he created the sketches to the wall mural 'Olympia - Mythos und Realität' (Olympia - Myth and Reality, 271 x 650 cm), in which Athena appears again and time periods overlap.