The King's Jewels

Once upon a time in the land of Puzzlania, there was a king who had twelve pentonimo crown jewels. The jewels were very expensive-looking. And beautiful. One fine day, the king decided he would give away his jewels to the wisest person in the kingdom. So, all the mages of the kingdom came, wearing hats that were blue and white.

The king showed all the mages the twelve jewels. "These are the twelve crown jewels of my kingdom. I shall go into my throne room and place seven of these jewels in a box, and then I shall cut three square holes in that box. I shall bring the box back, and give each of you a quill pen and a sheet of papyrus. Whoever is the first to use the quill pen to draw on the papyrus which seven jewels I have placed in the box, and how they are arranged, shall keep the jewels forever."

You are one of the mages. You like the expensive-looking beautiful crown jewels, so you desperately wish to solve this puzzle before the other mages. Which jewels did the king use, and what is their arrangement?