Japanese artist Tatsuo Horiuchi creates digital art in Microsoft Excel. As he neared retirement he decided to take up painting, but he wanted to save the cost of brushes and pencils, so he used a tool he already owned, Microsoft’s popular spreadsheet program.

“I never used Excel at work but I saw other people making pretty graphs and thought, ‘I could probably draw with that,'” he told My Modern Met. “Graphics software is expensive, but Excel comes pre-installed in most computers … And it has more functions and is easier to use than Paint.”

He began painting in Excel in the year 2000. “I set a goal,” he says, “in 10 years, I wanted to paint something decent that I could show to people.” After only six years he took first prize at the Excel Autoshape Art Contest, and he’s been at it now for more than 15 years.

He sells the digital paintings as limited-edition prints that you can see and purchase here.