You're helping someone arrange framed photos on a blank wall before hammering a single nail. Build a single-page widget where the user enters the **wall width** (in inches or cm) and then adds up to 8 picture frames by specifying each frame's width and a desired gap between frames. The app calculates and visually previews how the frames would be centered across the wall as a horizontal row, showing each frame as a labeled rectangle drawn to relative scale. Display the **starting x-position of each frame** (i.e., how far from the left edge to place each nail) and a clear warning if the frames are too wide to fit on the wall. The user can remove any frame from the list and the layout instantly recalculates. No backend, no auth — just one interactive page that solves the age-old 'where do I put the nail?' problem.