New Twiddle

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
}

styles.app\.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

.content-layout-content {
  background-color: red;
  width: 200px;
  height: 120px;
}
.content-layout-sidebar {
  background-color: green;
  width: 200px;
  height: 120px;
}

.foo {
  outline: solid 2px orange; 
}

.content-layout {
  border: solid 4px yellow;
}

templates.application\.hbs

<MyOtherComponent as |Content Sidebar|>
  <Content class="foo">
  
  </Content>
  <Sidebar class="foo">
  
  </Sidebar>
</MyOtherComponent>

templates.components.my-component\.hbs

<div ...attributes>
  {{yield}}
</div>

templates.components.my-other-component\.hbs

<div class="content-layout grid-container" ...attributes>
  {{yield (component "my-component" class="content-layout-content")
    (component "my-component" class="content-layout-sidebar")
  }}
</div>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}