.round(@radius:50%){
    border-radius:@radius;
}

.circle(@size:30px){
    .size(@size);
    .round();
}

.elipse(@width:30px,@height:30px,@radius:0){
    width:@width;
    height:@height;
    & when (@width >= @height ){
        .round(@width / 2);
    }
    & when (@width < @height){
        .round(@height / 2);
    }
}