node_modules/material-design-lite/src/grid/snippets/grid.html

<div class="mdl-grid">
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
  <div class="mdl-cell mdl-cell--1-col">1</div>
</div>
<div class="mdl-grid">
  <div class="mdl-cell mdl-cell--4-col">4</div>
  <div class="mdl-cell mdl-cell--4-col">4</div>
  <div class="mdl-cell mdl-cell--4-col">4</div>
</div>
<div class="mdl-grid">
  <div class="mdl-cell mdl-cell--6-col">6</div>
  <div class="mdl-cell mdl-cell--4-col">4</div>
  <div class="mdl-cell mdl-cell--2-col">2</div>
</div>
<div class="mdl-grid">
  <div class="mdl-cell mdl-cell--6-col mdl-cell--8-col-tablet">6 (8 tablet)</div>
  <div class="mdl-cell mdl-cell--4-col mdl-cell--6-col-tablet">4 (6 tablet)</div>
  <div class="mdl-cell mdl-cell--2-col mdl-cell--4-col-phone">2 (4 phone)</div>
</div>