 Complete the following phrase:  Around May 1895, Charles Seeberger began drawings on a form of escalator similar to those patented by Wheeler in 1892. This device consisted of flat, moving stairs, not unlike the escalators of today, except for one important detail: the step surface was smooth, with no comb effect to safely guide the riders feet off at the ends. Instead, the passenger had to step off sideways. To facilitate this, at the top or bottom of the escalator the steps continued moving horizontally beyond the end of the handrail like a miniature moving sidewalk until they disappeared under a triangular divider which guided the passenger to either side. Seeberger teamed with Otis in 1899, and together they produced the first commercial escalator. It won first prize at the 1900 Paris 