.parent{
    border: 1px solid black;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    /*flex-direction: column;*/
    /*flex-direction:row-reverse;*/
    /*justify-content: center;*/
    /*justify-content: flex-start;*/
    /*justify-content: flex-end;*/
    /*justify-content: space-between;*/
    /*justify-content: space-around;*/
    height: 350px;
}
.item1{
    background-color: aqua;
    width: 150px;
    height: 100px;
    /*flex: auto;*/
    /*align-self: stretch;*/
}
.item2{
    background-color: antiquewhite;
    width: 150px;
    height: 100px;
    /*flex: auto;*/
    /*align-self: stretch;*/
}
.item3{
    background-color: red;
    width: 150px;
    height: 100px;
    /*flex: auto;*/
    /*align-self: stretch;*/
}
.item4{
    background-color: green;
    width: 150px;
    height: 100px;
    /*flex: auto;*/
    /*align-self: stretch;*/
}