Students and staff crossing Polett Walk and 13th Street gathered to watch as dozens of skateboarders took turns performing tricks — sometimes in orchestrated pairs — on the giant “half-pipe” ramp. Whenever a highly technical maneuver was successfully landed, the celebratory sound of boards slapping against the lip of the half-pipe and clapping from on-lookers filled the area. A few inevitable hard landings drew grimaces from the crowd, but the participants always rose to their feet unharmed.