如何创建html不规则表格？

<table>
  <tr>
    <td></td>
    <td></td>
    <td></td>
  </tr>
  <tr>
    <td></td>
    <td></td>
    <td></td>
  </tr>
  <tr>
    <td></td>
    <td></td>
    <td></td>
  </tr>
</table>

table {
  border-collapse: collapse;
}

td {
  width: 100px;
  height: 50px;
  border: 1px solid black;
}

td:nth-child(1) {
  background-color: red;
}

td:nth-child(2) {
  background-color: green;
}

td:nth-child(3) {
  background-color: blue;
}

td:nth-child(4) {
  background-color: yellow;
}

td:nth-child(5) {
  background-color: orange;
}

td:nth-child(6) {
  background-color: purple;
}