1.container {
2  width: 80px;
3  margin: 100px auto;
4}
5
6.block {
7  position: relative;
8  box-sizing: border-box;
9  float: left;
10  margin: 0 10px 10px 0;
11  width: 12px;
12  height: 12px;
13  border-radius: 3px;
14  background: #FFF;
15}
16
17.block:nth-child(4n+1) {
18  animation: wave_23 2s ease .0s infinite;
19}
20
21.block:nth-child(4n+2) {
22  animation: wave_23 2s ease .2s infinite;
23}
24
25.block:nth-child(4n+3) {
26  animation: wave_23 2s ease .4s infinite;
27}
28
29.block:nth-child(4n+4) {
30  animation: wave_23 2s ease .6s infinite;
31  margin-right: 0;
32}
33
34@keyframes wave_23 {
35  0% {
36    top: 0;
37    opacity: 1;
38  }
39
40  50% {
41    top: 30px;
42    opacity: .2;
43  }
44
45  100% {
46    top: 0;
47    opacity: 1;
48  }
49}