int a = 0; int b = 1; int c = 2; int t = 20; void setup(){ pinMode(a, OUTPUT); pinMode(b, OUTPUT); pinMode(c, OUTPUT); } void loop(){ digitalWrite(a, HIGH); digitalWrite(b, HIGH); digitalWrite(c, LOW); delay(t); digitalWrite(b, LOW); delay(t); digitalWrite(c, HIGH); delay(t); digitalWrite(a, LOW); delay(t); digitalWrite(b, HIGH); delay(t); digitalWrite(c, LOW); delay(t); }