flexbox display items in a column code example

Example 1: flex align children to side

flex-direction: column;
align-items: flex-start; //left
align-items: center; //center
align-items: flex-end; //right

Example 2: whats the best ways to 3 x 3 perfects squares on a webpage using flexbox

.parent {
  display: flex;
  height: 300px; /* Or whatever */
}

.child {
  width: 100px;  /* Or whatever */
  height: 100px; /* Or whatever */
  margin: auto;  /* Magic! */
}