A moth fluttering its wings. A caterpillar curling up. They are among the gentlest movements in the natural world that the Contrast Club, a jewelry brand in Helsinki, Finland, has sought to capture in a series of new interactive designs.

The 18-karat gold rings, earrings and bracelets of the Lepidoptera Collection house tiny mechanisms that generate movement in response to force — such as a stroke or a nudge — without the aid of electricity or batteries.

For example, a pair of 18-karat yellow gold earrings about an inch long and a fifth of an inch wide hang straight from the earlobes, but curl softly into hoops when touched, mimicking “the gentle way a caterpillar moves itself away from danger,” according to the brand’s website.

The movement is produced by tiny hand-built bronze and stainless steel mechanisms inside each piece. When the earring is touched, the mechanism transfers that energy throughout the shape and the segmentation of the piece’s gold casing allows it to subtly bend. The earrings are 3,600 euros ($3,709) and can be purchased through the brand’s website.

James Cole and Suvi Ellila, who founded the brand in 2022, met at Aston University in Birmingham, England, where they both earned bachelor’s degrees in mechanical engineering in 2010.