 The school included architects such as Louis Sullivan and Dankmar Adler, William Le Baron Jenney, John Root, and William Holabird and Martin Roche, whose designs combined architectural aesthetic theory with practical commercial sense.They favoured placing rich, ornate designs on the outside of skyscrapers at the ground level and simpler, plainer ornamentation on the upper levels, with strong vertical lines.The roofs of their skyscrapers typically formed a comprehensible outline and structure when seen at a distance as part of the city skyline.