They like to cover window poles and rails.
Materials used are 6mm MDF, wood glue,panel pins, 15mm x15mm wood strips.
Step 1: Window Pelmets
Step 2: The Cutout
then use a sander to round off the edges.
Step 3: The build
Sand down and undercoat with matt emulsion.
Step 4: Keep it Clean
I use old remnants of wallpaper as dust sheets when painting.