Boy helps his dad build rollercoaster in back gardenPublished7 May 2014Image caption, This rollercoaster is in 10-year-old Lyle Pemble's backyard. He helped his dad design and build it.Image caption, The coaster is powered only by the force of gravity and is made of wood.Image caption, Lyle wants to work as a rollercoaster engineer when he grows up. The ride is nearly 200 feet long and took about six weeks to build.Image caption, Lyle's dad, Will, has made sure the ride is safe, it's called "The Caution Zone" because of all the safety features they've used. Definitely not one to try at home.