1、 单项目

首先，只有左上角有1个点的情况。Flex布局默认就是首行左对齐，所以一行代码就够啦。

左上角.png

.box {
    display: flex
}

设置项目的对齐方式，就能实现居中对齐和右对齐。

水平居中.png

.box {
  display: flex;
  justify-content: center;
}

设置交叉轴对齐方式，可以垂直移动主轴。

垂直居中.png

.box {
  display: flex;
  align-items: center;
}

水平垂直居中.png

.box {
  display: flex;
  justify-content: center;
  align-items: center;
}

水平居中底部.png

.box {
  display: flex;
  justify-content: center;
  align-items: flex-end;
}

右下角.png

.box {
  display: flex;
  justify-content: flex-end;
  align-items: flex-end;
}

2、双项目

.box {
    display: flex;
    justify-content: space-between;
}

.box {
    display: flex;
    flex-firection: column;
    justify-content: space-between;
}

.box {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
}

.box {
    display: flex;
    flex-direction: colunmn;
    justify-content: space-between;
    align-items: flex-end;
}

.box {
    display: flex;
}
.box .item:nth-child(2) {
    align-self: center;
}

.box {
    display: flex;
    justify-content: space-between;
}
.box .item:nth-child(2) {
    align-self: flex-end;
}

3、三项目

.box {
    display: flex;
    justify-content: space-between;
}
.box .item:nth-child(2) {
    align-self: center;
}
.box .item:nth-child(3) {
    align-self: flex-end;
}

4、四项目

.box {
     display: flex;
     flex-wrap: wrap;
     justify-content: space-between;
     align-content: space-between;
}

html结构为：
<div class="box">
  <div class="column">
    <span class="item"></span>
    <span class="item"></span>
  </div>
  <div class="column">
    <span class="item"></span>
    <span class="item"></span>
  </div>
</div>

css代码如下:
.box {
    display: flex;
    flex-warp: warp;
    algin-content: space-between;
}
.box .column {
    flex-basis: 100%;
    display: flex;
    justify-content: space-between;
}

5、六项目

.box {
    display: flex;
    flex-wrap: wrap;
    align-content: space-between;
}
.box .column {
    flex-basis: 100%;
    display: flex;
    justify-content: space-between;
}

.box {
    display: flex;
    flex-direction: column;
    flex-wrap: wrap;
   align-content: space-between;
}
.box .column {
    flex-basis: 100%;
    display: inline-flex;
    flex-direction: column;
    justify-content: space-between;
}

6、九项目

html结构为:
<div class="box">
    <div class="column">
        <div class="circle"></div>
        <div class="circle"></div>
        <div class="circle"></div>
    </div>
    <div class="column">
        <div class="circle"></div>
        <div class="circle"></div>
        <div class="circle"></div>
    </div>
    <div class="column">
        <div class="circle"></div>
        <div class="circle"></div>
        <div class="circle"></div>
    </div>
</div>

css代码为：
.box {
    display: flex;
    flex-warp: warp;
    justify-content: space-between;
}
.box .column {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}