Dice

25mm x 25mm Hardwood 1/4" secondary wood (optional) Workstation makes this a lot easier

Shaper Origin workstation 1/8" spiral cutter CA glue Sandpaper

I chose to cut the dice blanks on the table saw, makes very quick work of it. Cut more than you want, my first attempt took me 8 blanks to get 3 good ones. Took me a little wile to figure out clamping. On workstation I used one of the cams for tightening the spoil board as a stop and then set up a grid from there. That makes it easily repeatable. The clamps that come with workstation seem to work pretty well, I couldn't get double sided tape to really hold it down. This is shown in the 3rd pic I suggest you have a die with you so you can figure out the proper orientation Set up a grid and position each file at 0x,0y. Use the 1/8" cutter and cut the hole to what ever depth you like. I used 3mm, it should helix it for you. Flip the die and load the appropriate file for that side. One all 6 side are complete sand and round over corners as desired Also in the files is one labeled dots, if you want to make inlays for the holes this file will do it. I used 1/4 hardwood. The file should be set up to cut outside and a 0 offset worked for me. I cut the dots so there was a small amount still holding it (6mm on the shaper) and then popped them off with a chisel. If you cut them all the way out they get sucked up in the dust collector. I then placed a small drop of CA glue in the hole and set the dot in. Then used a belt sander to flush them up. Apply finish as necessary.