Heat Machine

Make your computer turn into a heat machine, to warm you on cold days.

I attempted this:

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
long long a, i;
for (i = 9999999; i > 1; i >> 1)
while (malloc(i))
a = a+i;
return 0;
}

It just freezes my laptop (which is under my blanket).
To heat, I think we must stress the CPU and GPU too. This only stresses the RAM, I think.

Show us your HEAT MACHINE