int led1 = 23;
int led2 = 22;
int led3 = 21;
int led4 = 19;
int led5 = 18;
int led6 = 27;
int led7 = 17;
int led8= 16;
int led9 = 4;
int led10 = 2;

void setup() {
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(led5, OUTPUT);
  pinMode(led6, OUTPUT);
  pinMode(led7, OUTPUT);
  pinMode(led8, OUTPUT);
  pinMode(led9, OUTPUT);
  pinMode(led10, OUTPUT);
}
void loop() {
  digitalWrite(led1, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led1, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                          // wait for a second
 
digitalWrite(led2, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led2, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                            // wait for a second                     
digitalWrite(led3, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led3, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                             // wait for a second                      
 digitalWrite(led4, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led4, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                         // wait for a second
 digitalWrite(led5, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led5, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                        // wait for a second
  digitalWrite(led6, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led6, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                         // wait for a second     
  digitalWrite(led7, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led7, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                         // wait for a second        
   digitalWrite(led8, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led8, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                          // wait for a second                                           
  digitalWrite(led9, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led9, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                                         // wait for a second       
  digitalWrite(led10, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(led10, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);  
                     }                     // wait for a second