yielding hash

components.my-component.js

import Ember from 'ember';

export default Ember.Component.extend({
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

left-component.component.js

import Ember from 'ember';

export default Ember.Component.extend({
});

left-component.template.hbs

<div>Left Component</div>
{{yield}}

right-component.component.js

import Ember from 'ember';

export default Ember.Component.extend({
});

right-component.template.hbs

<div>Right Component</div>

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{my-component parts=(hash left=(component 'left-component') right=(component 'right-component'))}}
<br>
<br>

templates.components.my-component.hbs

<h3>My Component</h3>
{{parts.right}}	
{{parts.left}}

twiddle.json

{
  "version": "0.10.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.8.0",
    "ember-data": "2.8.0",
    "ember-template-compiler": "2.8.0",
    "ember-testing": "2.8.0"
  },
  "addons": {}
}