The Standard grade student did not want to do just another box or chair and was discussing more creative options with friends and family.
It was his granny who came up with the winning formula when the teenager talked it over: "Make me something I can get round the house on. Something that's easy to use and I can stand up," she told him.
The Plockton High pupil headed for home and mulled things over. "I suddenly realised it was quite a good idea," says John, now in fifth year, preparing for Highers.
"I looked it up and realised there was nothing on the market like that at all. So I had to do a lot of research and of course it had to have a few aspects to it. It had to be very low off the ground because my gran suffers from arthritis and other things, so she finds it very hard to step up onto things.
"She has an electric scooter for outdoor use, but it's quite high, so she tends not to like to use it because it's quite painful to get up and down onto. So it had to be very, very low to the ground and it had to be easy to use and simple.
"I also wanted to provide the user with a standing position, because standing is the most prominent position you can be in. It provides the most independence that any position could give you and you are not being talked down to, when you are stationed in it.
"An electric wheelchair can get you round the house when you are sitting down. Some people use electric wheelchairs not because they can't stand up, but because they find it painful to walk. This would suit them perfectly because they can stand on it and they can get around the house.
"It's a very low platform electric scooter, only two centimetres off the ground. It's very stable, it's got three wheels - two at the back, one at the front for steering - and very simple controls. That's what I ended up with after a lot of research and a lot of design."
John visited a local day care centre for some of his market research and is now developing his third working prototype.
Last year, he won the Scottish regional finals of the Young Engineers For Britain Award with his Zoomer, which he describes as a cross between a Zimmer and an electric wheelchair. He went on to win three of the awards at the national final in London - one for product development and marketability, another for engineering less stressful and more efficient travel, and a third for engineering help for those in need.
No one was more pleased than Granny. "She was very chuffed," says John, who pocketed pound;1,000 for himself and pound;1,000 for his school in winnings.
John has design rights for the Zoomer and is currently awaiting design registration and looking for a manufacturer with the help of the Highlands and Islands Enterprise.
He paid tribute to the support he had had from his teacher Jamie Kean (see left): "He's an excellent teacher and he really does teach you to do your best and inspires creativity."
But John's inventiveness is also genetic. His father John is a window cleaner who has designed and built his own portable water pressure system.
"It's a huge water tank that fits into the back of his van and it has the pressure system and a pole system which is a series of telescopic poles with specialised brushes and water gear.
"Basically, he can do a full day's work from one van and can do three or four storeys from the ground. It's very, very interesting and very, very clever," says John (jnr) proudly.