One happy dog in Woodland Park has turned fetch into a neighborhood activity. Randi, a 5-year-old rescue owned by Michael Patterson, has an obsession with chasing tennis balls. He is known for wild jumps, occasional flips and other airborne tricks – all while in pursuit of the bouncy balls. Randi developed a habit of dropping the balls on the outside of Patterson’s waist-level fence, seemingly asking any passerby — old or young, stranger or friend – to throw it across the yard for him to retrieve. The ritual sparked an idea for neighbors Rick and Mary Crosslin after Patterson told them that he wished more people knew they were allowed to throw the balls for Randi. Randi, a 5-year-old rescue owned by Michael Patterson, has an obsession with chasing tennis balls. (Jessica Van Dyne) “I was upstairs one day, and I was like, ‘Who the heck is that out in my driveway,’” Patterson said. When the 78-year-old went outside, he found the Crosslins installing an empty flower box on the fence.…