#define VAR_1(a,b) a##b
#define VAR_2(a,b) VAR_1(a,b)
#define VAR(a) VAR_2(a,__COUNTER__)
int VAR(x) = 100;
int VAR(x) = 101;
int VAR(x) = 102;
int VAR(x) = 103;
void setup()
{
Serial.begin(115200);
Serial.println(x0);
Serial.println(x1);
Serial.println(x2);
Serial.println(x3);
}
void loop()
{
delay(10);
}