I don't know if there is a pattern here or online. Probably somewhere, it's a classic pattern. I got a book on it and it was very simple to do with jelly rolls.
The black of the end triangles is from the same collection but the black for the center squares is a different one. I had used the matching black for something else and didn't have enough. I think it was a happy accident to have the darker black in the squares, looks much better to me.