// our patch
SqrOsc s => LPF f => dac;
// not so loud
.05 => s.gain;
// set freq
500 => s.freq;
// set filter Q
10 => f.Q;

// infinite time loop
while( true )
{
    // print
    500 + 4500*.5*(1+Math.sin(now/second*5)) => f.freq;
    // every sample (for complete precision)
    1::samp => now;
}