Declaring and Relating a Variable

Hi there, before I start I want to say sorry @all, esp @william. I did not mean to sound snappy. I think I had been staring at the computer too long and my brain had stopped working. I punched in mAbs into search and found my answer this morning, when yesterday, as I say I must have been too tired because I could not find it. Anyhow, new day, new dollar!

I am studying the Breakout Tutorial, in it, the programmer has used a isPlaying call for his %trail.

$thebase.myTrail.isplaying=true;	
////but he also has this line. also in onLevelLoaded baseClass
%trail.playEffect(false);



///later in the baseClass onTimer() he uses these in the function as
function baseClass::onTimer(%this) 
	{
	    %speed = getword(%this.getlinearVelocitypolar(),1);
		if ( (%this.myTrail.isplaying==true) && (%speed < 5) ) 
		{
			%this.myTrail.stopEffect(true,false);
			%this.myTrail.isplaying=false;
		} else if ( (%speed > 5) && (%this.myTrail.isplaying==false) ) 
		{
			%this.myTrail.playeffect(false);
			%this.myTrail.isplaying=true;
		}
	}

my confusion is, what is he using the isPlaying for?
%speed it is true,&& speed is less than 5
he then sets it to false.
and if false and speed over 5 he sets it to true, but sets playEffect to false. I am confused about this as isn't playEffect() enough to use in this case? What is the purpose of the isPlaying bool?