int randNumber1 = 5;
int randNumber2 = 5;
int randNumber3 = 5;
int randNumber4 = 5;
int randNumber5 = 5;
int randNumber6 = 5;
int randNumber7 = 3;
int randNumber8 = 3;
int randNumber9 = 4;
int randNumber10 = 4;
int randNumber11 = 7;
int randNumber12 = 7;
When you start numbering variable names, it's time to start thinking about arrays.
unsigned long currentMillis1 = millis();
unsigned long currentMillis2 = millis();
unsigned long currentMillis3 = millis();
unsigned long currentMillis4 = millis();
unsigned long currentMillis5 = millis();
unsigned long currentMillis6 = millis();
6 copies of now is just plain dumb.
The last three pins all update the time stored in previousMillis4, though they depend on previousMillis4, previousMillis5, and previousMillis6.
Proper use of arrays would have made that impossible to copy/paste/edit incorrectly, since no copy/paste/edit would have been needed.