These screwy stools, called Vitae Stools, are the products of Italian design company Riva 1920.
Mimicking the shape and form of screws, these charming seats are crafted of American walnut wood or scented Lebanon cedarwood. The designers, as described on their website, strive to create natural-looking home furnishings that are "suffused with the scents of wood, oils and wax." They only use wood from sustainable forests and wood suppliers that have been accredited by the Forest Stewardship Council (FSC). Natural finishes are also used to create their pieces.
Further, as the name "Vitae Stools" suggests, these pieces allude to existence and the circle of life, which goes hand in hand with Riva 1920's dedication to sustainable production practices.