There's a Rubik's cube inside the test selection labyrinth for Wallabies coach Ewen "Link" McKenzie.
He may have the solutions after the candidates go out to upset and reinforce those notions tonight when the Waratahs host the Bumbies in their Super Rugby semifinal at Allianz Stadium in Sydney.
The biggest puzzle for McKenzie and the opening Bledisloe Cup test is his verdict on the men who will inhabit the nerve centre of his side, the blokes who will play No8, halfback, and five-eighths.
When the Wallabies played France in their June test series, Wycliff Palu, Nic White, Brendan Foley and Matt Toomua was the preferred combination. They were influential components in extending the side's winning sequence to seven.
They are on opposing sides tonight as the best Australian sides duke it out against a background of simmering acrimony connected to last year's in-house Wallaby tour.
Toomua played at second five-eighths for the Wallabies in June but the Brumbies believe he gives much stronger balance to their side when he is used closer to the action.
For many that decision, made by coach and former star Wallaby five-eighths Stephen Larkham, should be repeated in the Wallabies.
Others in the mix for the key international roles are the Tahs pair of halfback Nick Phipps and utility Kurtley Beale while the Brumbies' Christian Leali'ifano and reserve Pat McCabe both have wide support for their midfield value.
Brumbies captain and No8 Ben Mowen is out of test reckoning because he is heading offshore while others being touted for that role are Scott Higginbotham and Ben McCalman whose campaigns with the Rebels and Force have finished.
At almost 32, Palu has played 51 tests for the Wallabies. He has a reputation to match his strong physique but that has been glimpsed infrequently in Bledisloe Cup combat and there is a murmur Higginbotham has greater range to his game.
Without the injured Will Genia and Quade Cooper, the choices have narrowed for players asked to control the flow of the Wallabies patterns.
White has a useful pass, a strong kicking game, speed and a big heart which serve the Brumbies template and he is in the chair for test work in the Rugby Championship. There are questions about his "feel" for a game and his feisty temperament but a change in role with the Wallabies should refine those.
Outside him, Toomua loves to play flat and challenge the line in attack and he is very spirited on defence though he can rush out of the line in his haste to nail an opponent. Foley is more measured about his play and has sharpened his goal-kicking with genuine speed to take a gap.
If McKenzie wants to play the dual pivot game then Foley and Toomua fit his plans which means bench roles at best for Beale and McCabe. There is a mercurial edge about Beale's game but when matches get tighter, as they do in Bledisloe combat, his tackling flaws may be a liability.
McCabe is usually solid in those duties and runs great angles while Toomua has those qualities and a kicking game which allow him to fill the midfield role too.
For McKenzie it is about analysing their styles and projecting who suits his test plans while for those who rock up to Allianz Stadium tonight, it is all about who does the business for the Brumbies or Tahs.