Maker here. This was a project I worked on about a year ago. I didn't like building UIs for simple projects (e.g. desktop apps). At work - we use Powerpoint to generate quick specs. I wanted to quickly be able to take those and convert them to working models. It's not perfect by any means - but the output is readable html and css. Challenges with the project include parsing the actual PPT and XML structure. A few other projects exist - but they weren't structured to be super extensible or readable. Powerpoint has a lot of elements - so I would use basic rectangles for now.