Hints: We once had another plant of the same genus for a Seed of the Week.
The seeds have a similar squarish shape, although they were a different color. These seeds are formed in a pod (I don't have a photograph of one.)
The brilliant yellow flowers of this small desert tree also resemble that of its orange-red relative, although its relative is a large shrub.
Can you guess what tree these seeds are from?
Edit: the answer is now posted.