With the corner block beveled on all sides, it is time to add an arc. On the two edges on the top face that meet the bevel faces, draw marks at the middle point (see photo). The marks should be 1 3/8" from the outside edges.

Using a round object that has approximately a 4" radius, connect the marks to create an arc. The corner will be cut off beyond this arc.

Tilting the band saw table to 45 degrees, carefully cut the corner off, staying just next to the line. For me, it was difficult to create a perfect arc, but I knew I would be cleaning it up by sanding, so it wasn't a big deal.

On a 1" benchtop belt sander, the table also was tilted 45 degrees and the vertical plate behind the belt was removed to make the belt give more when sanding. I turned the corner pieces upside down and gently moved the piece back and forth to even out the arc.

Repeat for all remaining 23 pieces.

Unfortunately I do not have process photos of the center pieces, but the method is relatively the same. A 3/8" thick board was used and cut down to 1 1/4" wide pieces with a 45 degree bevel along one edge. These are then cut into 24 pieces, each 3" long with square sides.

The same round object is then used to draw an arc from corner to corner on the edge opposite the bevel, but the same face as the bevel (hopefully that makes sense). Since this pieces is too small for me to comfortably cut on the bandsaw with it tilted and there is not much material being removed, I found it easiest to just sand away the material on the belt sander. With the table still tilted on the sander, place the piece flat on the table with the drawn arc side up. Slowly sand away the material until you get back to the line. Sand the tips off each of the pointed corners that are left behind after making the arc. Photos that show the finished center piece are shown on step 9.