naming_purpose_alpha.scss

$COLOR_RED: #FF0000;
$COLOR_GREEN: #00FF00;
$COLOR_BLUE: #0000FF;

$House_HEIGHT: 20px;
$House_Door_HEIGHT: 6px;

@function House_Window_color($color) {
    @return darker($color, 50%);
}

@mixin House_Window($color) {
    border-color: House_Window_color($color);
}

@mixin House($color) {
    &_LeftWindow { @include House_Window($COLOR-RED); }
    &_RightWindow { @include House_Window($COLOR-GREEN); }

    &_Door {
        height: House_Door_HEIGHT;
    }

    background-color: $color;
    height: $HOUSE_HEIGHT;
}

.MyHouse {
    @include House($COLOR_BLUE);
}