Lightning Web Component, Nested Child Components event Handling

Model3.css

div{
    background-color: #ddd; 
}

Model3.html

<template>
    <div onclick={customClick}>
        This is Model 3 Component , Click Me -  {log}
    </div>
</template>

Model3.js

import { LightningElement, track } from 'lwc';
export default class Model3 extends LightningElement {
    @track  log = '';
    customClick() {
        const event = new CustomEvent('modelclick', {
            // detail contains only primitives
            detail: 'Event Started in Tesla Model 3'
        });
        // Fire the event from model 3
        this.dispatchEvent(event);
        this.log = ' - Model 3 clicked';
    }
}