I've been watching the twins dating show "Twin Love". Yes it's a low quality dating show, but it's borderline a scientific study on twins. They separate the twins so that each twin is in a separate house, isolated from their other twin. Then each twin dates other twin people, all of whom are separated from their twin. At first there's only one complete match of a 2x2 or 2² perfect twin match. But the game pushes them into each dating the same set of twins, by eliminating people who aren't matched (there are brief moments where the twins can see each other). The twin pairs start to fall in line making complete pairs. Basically they put a bunch of twins together and then use extreme social pressure to make the twins form twins of twins.