Cologne 2015: Munich design studio Formstelle has created a subtly patterned lounge chair for iconic furniture brand Thonet.

Inspired by "collars, covers, shells and underwater worlds", the Lounge Chair 808 comprises a hard outer shell surrounding quilted upholstery.

The upholstery features a "wave effect" contour developed by Claudia Kleine and Jörg Kürschner of Formstelle especially for this product.

"We tested many sandwich cushion structures with different pillow fillings in collaboration with Thonet's upholstery workshop," Kleine and Kürschner told Dezeen. "The final high grade upholstery consists of integrated springs and a well-balanced combination of foam materials."

The designers then worked with German textile manufacturer Rohi to create a bespoke woollen yarn with honeycomb structure for the chair.

The fabric, called Soul, is available in thirteen colours, with further material options including leather, fabric and formed fleece, and matching decorative seams.

The internal structure is made using rotationally moulded thermoplastic resin and a layer of polyurethane foam moulding.

The frame of the lounge chair is available in wood with bentwood elements, flat steel, or tubular steel in various colours. A mechanism hidden inside enables multiple seat and backrest positions, including a full recline. An auto-return spring brings the chair back to its original position.

"The chair was inspired by a simple longing for furniture that brings us to a state of contemplation," said the designers.

The Thonet Lounge Chair 808 will debut at the imm Cologne trade fair in January 2015.