1 All blue boxes are 100x100px with box-sizing: border-box and 2px border (4px border-top), we expect offsetWidth/Height to be 100x100
2 flex-flow: default, orange box has width: 300px
5 flex-flow: default, orange box has width: 400px
8 flex-flow: default, orange box has width: auto
11 flex-flow: default, orange box has width: auto, flex-box has box-sizing: border-box
14 flex-flow: column, red box has height: 300px
17 flex-flow: column, red box has height: 400px
20 flex-flow: column, red box has height: auto
23 flex-box has box-sizing: border-box and flex-wrap: wrap;
26 flex-box has box-sizing: default and flex-wrap: wrap;
29 flex-flow: column, flex-box has box-sizing: border-box, flex items have flex: 1