Sears decided to focus their initial occupancy on housing their merchandise group, renting out the remaining space to other tenants until needed. The latter floor areas had to be designed to a smaller footprint with a high window-space to floor-space ratio to be attractive to prospective lessees. Smaller floorplates required a taller structure to yield sufficient square footage. Skidmore architects proposed a tower with large, floors in the lower part of the building with gradually tapered floorplates in a series of setbacks, which would give the tower its distinctive look.