Will Pemble's son asked if they could build a coaster in their backyard. He didn't have a good reason why not.

Ten-year-old Lyle Pemble's love of roller coasters started last summer when he rode one in New Jersey.

Since then, the California youngster "started doing research on them" to try and find the best one.

That's when he asked his dad, Will, if they could build one in the backyard.

"I started building the coaster because, Lyle, my son asked me if we could, and I couldn’t think of a good reason to say no,” Will Pemble said.

Fair enough.

Will went on to explain to KPIX TV in San Francisco that building the coaster helped his son with math, physics, and science, because it made the problems more exciting. "So if there’s a coaster at the other side of how many feet of track do we need…then suddenly the word problem gets done really fast," he added.

That's the best reason I've ever heard, "why not?"

What a cool dad! I bet Lyle is the coolest kid in the neighborhood.

In case you're wondering what it costs to build a backyard coaster, Will says he coughed up about $3,500 to build what he calls The Caution Zone.

You can go to Will's YouTube page to see step by step videos of how he built The Caution Zone. Maybe you'll be inspired to build your own!