File content as of revision 2:7b860e46bf67:

#include "mbed.h"
 
DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
Thread thread(osPriorityHigh);
Thread thread3(osPriorityNormal);
Thread thread4(osPriorityLow);
 
void led2_thread() 
{
    double x, y =1.99, z=0.99;
    while (true) {
        led2 = !led2;
        wait(0.5);
        
        for (int j=0; j<100; j++)
            for (int i=0; i<100; i++)
                x = y*z+x;
        
    }
}
void led3_thread() 
{
    double x, y =1.99, z=0.99;
    while (true) {
        led3 = !led3;
        wait(0.5);
        
        for (int j=0; j<100; j++)
            for (int i=0; i<100; i++)
                x = y*z+x;
        
    }
}

void led4_thread() 
{
    double x, y =1.99, z=0.99;
    while (true) {
        led4 = !led4;
        wait(0.5);
        
        for (int j=0; j<100; j++)
            for (int i=0; i<100; i++)
                x = y*z+x;
        
    }
}
 
int main() {
    thread.start(led2_thread);
    thread3.start(led3_thread);
    thread4.start(led4_thread);
    osThreadSetPriority(osThreadGetId(), osPriorityBelowNormal);
     double x, y=1.99, z=0.99;
    while (true) {
        led1 = !led1;
        wait(0.25);
        for (int j=0; j<200; j++)
            for (int i=0; i<200; i++)
                x = y*z+x;
        
    }
}