per any pair of countries /
switch indicator /
like a turning table /
"advantage" /
"whose move?" /
or per any particular border crossing /
potentially many applications /
but not novel /
see, video/game design /
/programming /
/rule books /
rather /
than scholarly journals /
peer-reviewed theory papers /
see the game designs in depth /
then write the academic paper, or marketable book /
/end /

what does x represent?
(If not a dimensional analysis exercise where all units of measure cancel out and the quantity and qualitative of x has units null)
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