A former aerospace engineer puts his expertise to good use even in his retirement days by building roller coasters in his backyard for his grandchildren!
Paul Gregg who worked for Boeing for 34 years has designed and built three different rides in the back garden of his home in Seattle.
Gregg built the fun rides out of timber and metal. One car looks like a rocket while the other one looks like a mini racing car.
Following the completion of the roller coasters, he took a video of his grandchildren testing out the roller coasters and uploaded it
He has to push the cars up the first hill himself before the cars pick up momentum and move around the track by themselves
Looks like his project gets a full approval from his excited grandchildren!
Watch how the DIY roller coasters work here