The difference from a normal FIDE-pieces-versus-non-FIDE-pieces variant is
that both players can visualise their own pieces as FIDE ones - and, by
looking at the board in a slightly different way, their opponents' ones as
well. They don't have to think of one side's 'Rooks' as compounds of a
Rookfiler and half a Bishop, and 'Bishops' as filebound compounds of a
Rookranker and a quarter of a Nightrider, and 'Knights' as fileswitching
compounds of half a Ferz and a quarter of a Buffalo! They don't even have
to notice - as I did only while plotting out these moves - that one
player's division into odd and even ranks is the other player's Bishop
colouring.