Audiovisuals with SC - Example08b - faster is slower

//Example08b - faster is slower
//only one line differs from Example08a. the one in the main loop where we invert the mapping.
(
s.latency= 0.05;
s.waitForBoot{

//--window setup
var width= 640, height= 480;
var w= Window("Example08b - faster is slower", Rect(99, 99, width, height), false);
var u= UserView(w, Rect(0, 0, width, height));

//--variables
var pat= Pn(Pshuf(#[0, 0, 0, 0, 0.1, 0.25, 0.5, 0.75, 1, 1], 8), inf).asStream;
var syn= SynthDef(\av, {|rate= 1|
var x= Decay2.kr(Impulse.kr(rate), 0.01, 0.1, 2, 0.2);
var z= LPF.ar(LFSaw.ar(#[300, 301, 80, 81]).mean, 2000, x);
Out.ar(0, Pan2.ar(z));
}, #[0.05]).play(s); //short lag time to avoid clipping
var posx= 0;
var fre= 0;

//--interface
~radius= 100;
~fps= 60;
~spreadx= 100;

//--main loop
u.drawFunc= {
if(u.frame%~fps==0, { //pick a new frequency only once per second
fre= pat.next; //get the next value from the stream
syn.set(\rate, 1-fre*4+1); //send to the synth
});
posx= sin(u.frame*(fre+1)%50/50*2pi);
Pen.translate(width*0.5, height*0.5); //offset drawing to the centre
Pen.fillColor= Color.white; //always fill with white color
Pen.fillOval(Rect.aboutPoint(Point(posx*~spreadx, 0), ~radius, ~radius));
};

//--window management
u.clearOnRefresh= true;
u.background= Color.black;
w.onClose= {syn.free};
w.front;
u.animate= true;
CmdPeriod.doOnce({if(w.isClosed.not, {w.close})});
};
)

//change these while the program is running
~radius= 200;
~radius= 50;
~spreadx= 250;
~radius= 15;
~spreadx= 40;

//close the window to stop or press cmd+.