```javascript import _ from 'src/external/lodash/lodash.js'; const options = [1, 2, 3]; aexpr(() => { let x = 0; options.forEach(y => x+=y); lively.notify("x: " + x); return x; }).onChange(lively.notify); options[0]++; options.values() ``` Creating the hook triggers the AE Evaluation, which creates a hook and so on