Upholstery adds a personalizing touch to designer Chris Martin's smart rethink of the redoubtable shell chair, here with a tubular steel frame. Massproductions' cofounder-designer squares off the classic contours and adds a solid-wood bar across the top in a move that that he compares to the serif on a letterform. To complement the range of fabric and leather choices, the seating comes in several pairings of woodgrain and metal finishes.