// sinusoids are the eigenfunctions of LTI systems
SinOsc s => ResonZ f => dac;

// set filter parameters
1000 => s.freq;
10 => f.Q;

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