At the outset of thin shell root construction in the United States, it seemed that domes would be the order of the day for decorative applications and barrels for utilitarian buildings. However, a the hyperbolic paraboloid as a thin shell roof type is making inroads in these markets. The growing popularity of this roof is rooted in a seemingly contradictory characteristic of its shape. Although the hyperbolic paraboloid is curved in two directions, it is composed entirely of straight lines! This characteristic of the hyperbolic paraboloid spells outstanding savings in both construction materials and time, as well as engineering man hours.