The six-member Liljenquist clan arrived at Shadle Aquatic Center a half-hour before open swim began Monday afternoon, anticipating the crowds for a day of free swimming. As his older siblings splashed in deeper waters, 3-year-old Marcus bounced in the shallows near his mom, Teresa, who pointed a digital camera in his direction. “He wants to go down the slides and off the diving board, but they won’t let him,” Teresa said as Marcus, goggled and grinning, ran up and embraced her legs.