Combine a kid with a passion and a dad who just can't say no, and the result for one California family is a homemade roller coaster in a backyard.
After an inspiring trip to an amusement park, 10-year-old Lyle Pemble asked his dad Will if they could build a roller coaster at their home in Orinda, just outside San Francisco.
After some consideration, the father decided to take on the ambitious project.
"I thought about it for a second and the answer anyone expects is 'of course not'… but I said yes! I said sure!" he told ABC News.
The coaster - named "The Caution Zone" as a testament to the ride's rigorous safety precautions - is nearly 200 feet long and took about six weeks to build.
It is powered only by gravity and reaches a maximum speed of 14 mph.
Pemble said his son Lyle is "the brains" of the operation, and has contributed a great deal to the planning and execution of the project.
"He's a studier. My son knows everything there is to know about roller coasters. He helps design them and does the math," he said.
Since completing the original coaster last year, Will and Lyle have started building a second coaster in a friend's backyard. In a video posted to YouTube, Lyle walks with a friend and outlines design plans for the new structure.
"We're going to tilt the track to the side … so there would only be force pushing you down," he says in the video.
And there may be many more coasters to come for the Pemble family. Will said Lyle has built hundreds of designs on a simulation program and already has plans to build roller coasters as a profession when he grows up.