What is process.memory giving ?

Hello,
I tried it (see source) and got memory usage of 199, which is close to 4k or 3k by subtracting 4 bytes/block. Sourcecode is less than 400 bytes only.
Trace is not a help for me, my knowledge about that is too poor.
Checked memory-usage:

1. function Blinker only: usage is 60
   
2. function Blinker with LED1: usage is 132
   
3. function Blinker with LED1, LED2: usage is 199
   
4. function Blinker with LED1, LED2, LED3: usage is 265
   
5. used Blinker as module and required for LED1: usage is 178
   
6. used Blinker as module and required for LED1, LED2: usage is 252
   

7. used Blinker as module and required for LED1, LED2, LED3: usage is 326

   
   function Blinker(pin,frequency){
   var me = this;
   me.iv=-1;
   me.status = true;
   me.dur = 1000 / frequency;
   me.stop = function(){
   pin.write(false);clearInterval(me.iv);
   };
   me.start = function(){
   iv = setInterval(function(){
     me.status = !me.status;pin.write(me.status);
   },me.dur);
   };
   this.start();
   }
   var b = new Blinker(LED1,2);
   var c = new Blinker(LED2,5);