#include <SoftPWM.h>
uint8_t leds[10] = {2,3,4,5,6,7,8,9,10,11};

void setup(){
  
  SoftPWMBegin();
  for (int i = 0; i < 10; i++){
    SoftPWMSet(leds[i], 0);
  SoftPWMSetFadeTime(ALL, 50, 400);
  }
}

void loop(){
  for(int ix=0;ix<10;ix++){
  SoftPWMSet(leds[ix], 255);
  delay(50);
  SoftPWMSet(leds[ix], 0);
 }
 for(int ix=8;ix>0;ix--){
   SoftPWMSet(leds[ix], 255);
   delay(50);
   SoftPWMSet(leds[ix], 0);
 }
}