bool blueLedState = false;
bool redLedState = false;
unsigned long time, lasttime, prd;
void setup() {
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, INPUT_PULLUP);
}

void loop() {
if (!digitalRead(4)){
 blueLedState = !blueLedState;
 delay(100);
}

digitalWrite(3, blueLedState);

time = millis();

if(time - lasttime >= prd){
redLedState = !redLedState;
lasttime = time;

}
digitalWrite(2, redLedState);
}