Hi,

We have a staircase in our apartment which is around 12cm (4.7 inch) away from the wall. We'd like this area to be a part of the stairs/wall and not be kept as a gap. Any ideas on how to fill this gap in a way that wouldn't look like a fix?

Here's a photo of the gap:

Some additional photos:

• https://drive.google.com/file/d/1hmOBTdoPvnPktBBdPfY6LRnBi87Aw0RJuw/view?usp=sharing

• https://drive.google.com/file/d/1e_tgkku7IQr_oI5YWwTaDYYBfcFx51g-OA/view?usp=sharing
• https://drive.google.com/file/d/1JpyiZk6eiHDNjtLGqVc_UWoMwI7wo7oF8Q/view?usp=sharing

Thanks!