I’ve had several different designs for the roundel panels in the console room. The first attempt had ˝ inch MDF screwed to 1x8 pine planks. The inner edges of the roundels were 4” strips of 1/8” bathroom board cut very carefully to size and jammed into the hole. This really didn’t work very well as I had to tack them in place and the bathroom board was too hard to make the nails flush. Also I never did really figure out how to fit lighting behind that version. I made one panel as a prototype and ended up cutting it up and throwing it away. The white backing was the smooth white lighting diffuser material (acrylic or styrene – both work, though the acrylic is stronger and more flexible).
The next design was much more refined. I cut two ˝” MDO panels (plywood with a paper veneer) with roundels and placed 1” spacers between them (to reduce weight – 2” thick solid material would have been great but terribly heavy). The roundels are lined with smooth lighting diffuser sheeting cut on a table saw. I cut them slightly long and then trim them by the millimetre until they snap into place and hold tight without gluing. Some I did actually glue with caulking, others I didn’t bother.
Earlier panels were cut with a jig-saw, but a router works much better... I stapled 2x4 foot sheets of lighting diffuser behind them. They split, but not enough to show on the outside.
The panels are nine feet tall – the roundels are on a 24” grid and are 20.5 inches in diameter. The panels with 3 roundels wide are thus fairly unwieldy, though I’ve been able to move them without assistance. Plywood comes in 48x96 inch (4 foot by 8 foot) pieces, so I tiled the area with several of them, then tiled them differently on the reverse side for extra strength. Wherever there’s a seam on one side there’s unbroken wood on the other side, so in spite of being joined, even the large panels are quite rigid. I used spackling paste and wood filler to cover the joins and screws and glued the spacers in place also. I've since discovered that my roundels are too large - the ones in the show were 18" (presumably on 21" spacing).
Here's a panel being assembled - actually all held together with glue, but largely hollow so it doesn't weigh too much.