[woodcote]

Maybe a systematic testing of all possibilities is required?

1. Red to red / Black to black / White to white
   
2. R-r / B-w / W-b
   
3. R-b / B-w / W-r
   
4. R-b / B-r / W-w
   
5. R-w / B-b / W-r
   
6. R-w / B-r / W-b
   

If none of those work, it's something else!