File content as of revision 1:ef00f07599d7:

#include "mbed.h"

DigitalOut a(LED1);
DigitalOut b(LED2);
DigitalOut c(LED3);
DigitalOut d(LED4);
int main() {
    while(1) {
       int q=1,w=2,e;
       e=(q*q)+(w*w)-(2*q*w);
       switch(e)
       {
       case 1:
       a=0;b=0;c=0;d=1;
       wait(0.2);break;
       case 2:
       a=0;b=0;c=1;d=0;
       wait(0.2);break;
       case 3:
       a=0;b=0;c=1;d=1;
       wait(0.2);break;
       case 4:
       a=0;b=1;c=0;d=0;
       wait(0.2);break;
       case 5:
       a=0;b=1;c=0;d=1;
       wait(0.2);break;
       case 6:
       a=0;b=1;c=1;d=0;
       wait(0.2);break;
       case 7:
       a=0;b=1;c=1;d=1;
       wait(0.2);break;
       case 8:
       a=1;b=0;c=0;d=0;
       wait(0.2);break;
       case 9:
       a=1;b=0;c=0;d=1;
       wait(0.2);break;
       case 10:
       a=1;b=0;c=1;d=1;
       wait(0.2);break;
       case 11:
       a=1;b=0;c=1;d=1;
       wait(0.2);break;
       case 12:
       a=1;b=1;c=0;d=0;
       wait(0.2);break;
       case 13:
       a=1;b=1;c=0;d=1;
       wait(0.2);break;
       case 14:
       a=1;b=1;c=1;d=0;
       wait(0.2);break;
       case 15:
       a=1;b=1;c=1;d=1;
       wait(0.2);break;
       
       }
       
    }
}