*{
    padding: 0;
    margin: 0;
}
#game{
    width: 300px;
    height: 350px;
    border: 1px solid black;
    margin: auto;
    overflow: hidden;
}
#solid{
    width: 30px;
    height: 400px;
    background-color: red;
    position: relative;
    animation: solid 2s infinite linear;
}
@keyframes solid{
    0%{left:400px}
    100%{left:-50px}
}
#pit{
    width: 50px;
    height: 100px;
    background-color: white;
    position: relative;
    animation: solid 2s infinite linear;
}
#player{
    position: absolute;
    width: 15px;
    height: 15px;
    background-color: black;
    border-radius: 70%;
}