public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof YInterval)) {
            return false;
        }
        YInterval that = (YInterval) obj;
        if (this.y != that.y) {
            return false;
        }
        if (this.yLow != that.yLow) {
            return false;
        }
        if (this.yHigh != that.yHigh) {
            return false;
        }
        return true;