It didn't take long for diner operators to latch on to an important market niche-daytime customers. But as the mobile diners lingered into the late morning to take advantage of early risers and then the lunch rush, they began to clog the streets, congesting traffic. The solution was to move a few paces off the street onto a small plot of land, and to settle down semi-permanently. If business dropped off, the wagon could be moved to a new location. In the early 1900s, diners grew into their familiar shape, and later added "tables for ladies" who didn't feel comfortable on stools. The menus expanded along with the diners themselves, and the 1920s and 30s brought not only easy-clean surfaces but also the first soda fountains.