.beat {
    display: inline-block;
    background: url(music_note.jpg) no-repeat;
    width: 120px;
    height: 120px;
}

.beat_4 {

}

.beat_8x2 {
    background-position: -120px 0;
}

.beat_16x4 {
    background-position: -240px 0;
}

.beat_4rest {
    background-position: -360px 0;
}

.beat_8rest_8 {
    background-position: -480px 0;
}

.beat_8_8rest {
    background-position: -600px 0;
}

.beat_8_16x2 {
    background-position: 0 -120px;
}

.beat_16x2_8 {
    background-position: -120px -120px;
}

.beat_8_16_8 {
    background-position: -240px -120px;
}

.beat_8p_16 {
    background-position: 0 -240px;
}

.beat_16_8p {
    background-position: -120px -240px;
}