body{
  background-image: url("pattern2.jpg");
}

.kwadrat{
       width: 300px;
    height: 300px;
    border: 1px solid black;
    margin: 20px;
}

.pierwszy{
background-image: radial-gradient(white, black, blue);
}
.drugi{
    background-image: url(las.jpg);
background-color: aqua;
}
.trzeci{
    background-color: aquamarine;
    background-repeat: no-repeat;
    background-size: cover;
    overflow: scroll;
}
.czwarty{
    background-image: linear-gradient(white,black);
}