As I was assembling the ground floor/base, I remembered some tile samples I'd been given a few years ago. One of them looked to be perfect for the entrance to the Bohemian Inn. The tiles are quarter-inch cubes, which wasn't so perfect, but I had an idea.
I took the tiles off the backing board. Luckily, they were firmly attached to the net backing, so they stay in formation. I had to take a couple rows from the right side to make the pad come out right. It's a little messy, but this part of the tiles will be under the stairs, so it doesn't really matter. Here is the final design. It's glued to a piece of cardboard larger than the tiles and grouted with a brick red grout. In this photo, the left side has been sealed with a semi-gloss polycrylic. It makes the colors pop. I think once it's in place and the floor gets sealed, I'll switch to a satin finish.
I made a frame, stained it, and glued it around the tiles. The smaller clamps are holding shims, also glued.
The next photo shows the base face down with more shims being glued under the floor. I think with those in place, the tile section in its frame should fit flush with the floor. It worked during the dry fit. Notice the brace to the left of the hole. I was afraid it might be under the tile, but it worked out just fine.