They come from the same rugby hemispheres but play in the Rugby World Cup from different planets.
South Africa and Australia, who clash on Sunday, are Tri-Nations cohorts yet stand for rugby of very different styles.
For all the talk of the north v south divide - one fuelled by the odd media rant and the antipathy New Zealand and England inspire from afar - this tournament is showing clear divisions within divisions.
Wales and Ireland have produced among the best and most committed rugby at this World Cup, in marked contrast to the stodge dished up by their Six Nations mates England, Scotland, and Italy plus France's half-hearted campaign.
Nowhere is the game plan more diverse, though, than in the comparison between South Africa and Australia.
South Africa, with a muscular pack, stood up strongly against a brilliant Samoan assault at Albany, unlike Australia who wilted in Sydney this year.
Under pressure, the Springboks sent up bombs. Their centre Jaque Fourie often leads an up-and-in defensive method. Australia struggle physically to move the ball around and try to rely on guile. Their defence is patterned more than confrontational.
South Africa are certain to look to their scrum and lineout, plus the maul, to smash and tire a weak Australian pack. The Wallabies will attempt to pull backline tricks around Quade Cooper, with brilliant fullback Kurtley Beale the ideal man to test the South African defensive system.
Digby Ioane, one of the in-form Wallabies this season, should return after an operation on a broken thumb suffered in the opening Pool C match against Italy. Captain James Horwill said yesterday: "He's one of those guys that whenever the opportunity arises he's good to go. He doesn't need any warm-ups or anything like that."
Ioane has flourished with the Wallabies, on the flanks or angling off the wing hunting for inside passes and broken defensive lines.
His progress this year is in stark contrast to that of Springbok ace Bryan Habana, who has been turned into a kick-chaser. Habana should be a greyhound but is used as a retriever.
Both sides have dominant halfbacks but in different ways. Fourie du Preez's mere presence is essential for the Boks but his specialty kicks are negated by rule changes and he is on the down slope and hesitant of late. In contrast, the still rising Will Genia is a Wallaby trump card via his running and incisive decision-making.
Nowhere are the differences more marked than at first five-eighths. Morne Steyn showed out as a brave defender against Samoa, and he is a conservative controller and master goalkicker up to about 45m. Quade Cooper is magical with the ball, and also crazy especially when cornered near his goal-line.
The Wallabies hide Cooper in defence as a de facto fullback, although this sometimes gets them into more trouble than it is worth. His goalkicking, if needed, is flaky as is James O'Connor's.
There are the odd similarities. David Pocock and Heinrich Brussow are the best turnover flankers in world rugby.
Full-steam-ahead Pat McCabe, who will probably return from a shoulder injury for Australia on Sunday, is a South African type of second five-eighths (although the alternative, Berrick Barnes, is not).
Back to the differences. Coach Robbie Deans is all-powerful, has rebuilt the Wallabies and even changed his captain on the eve of the tournament. Peter de Villiers relies on other coaches, old-guard player power and resists endless calls to replace John Smit.
Deans doles out words the way Don Brash gives out benefits. De Villiers is the most quotable coach in rugby, and added to his legacy by claiming the key to stopping Cooper is giving him too many options.
De Villiers might be revealing the Springboks' tactics, and he might not. He is almost certainly trying to mess with Cooper's head.
Coaches' words and actions can be as different as the Australian and South African playing styles.
They often speak for effect, to win tactical wars, boost players' confidence, or put their teams on red alert. They use the public as a vehicle to get messages overt and subliminal across to players.
Coaches must also adapt to the weather. The rain bucketed down at times in Wellington yesterday. Further rain and southerlies are predicted this week.
Springboks v Australia
Wellington, 6pm Sunday