The first three were invented by one of the cleverest engineers audio has ever seen, Alan Blumlein. Blumlein invented so many things that it's difficult to know where to start, but what concerns us here is his considerable contribution to microphone techniques. Details are to found in his justly famous patent B.P. 394,325 that was applied for as long ago as December 1931.
The techniques described are the main ones that we use. They are also capable of variation according to the situation in which they are used. For example, one can ear space otherwise Coincident figure of 8's angled at 90 degrees for greater spaciousness. This is particularly useful if the recording will be replayed via headphones which requires the re-creation of the inter-aural phase differences we experience in the concert hall.