#include <reg51.h>
void main()
  {
    while(1)
      {
        P1 = 0x66
        MSDelay(100)
        P1 = 0xCC
        MSDelay(100)
        P1 = 0x99
        MSDelay(100)
        P1 = 0x33
        MSDelay(100)
      }
  }