Ok, to answer my own question:
To achieve alternating results, you can count the unique values in all the cells above including the current one.
The following formula achieves this for two alternations:
=ISODD(SUM(IF(FREQUENCY($A$1:$A1;$A$1:$A1)>0;1)))
=ISEVEN(SUM(IF(FREQUENCY($A$1:$A1;$A$1:$A1)>0;1)))
You could use MOD
and CHOOSE
to allow for virtually an unlimited amount of alternatives.
The formula needs to be dragged down, the second A1 will change to A2, etc.
It is calculation intensive, so it often times takes a long time until all calculations are performed, especially if you got a long list of data.
I hope that helps.