Distance between arduinos

Robin2:
... but I can't figure out the rationale for any of it. Meaningless names like EU and CR don't help.

European Union and Croatia?

I will never understand why anyone would use cryptic names for variables that means something only to the programmer. And the programmer is likely to be scratching their head a year from now and wish that they had commented the code better.

Which is easier to read?

x = analogRead(0);

sensorValue = analogRead(sensorPin);