Curve saw blade / saw blade

Traditional big mechanic scroll saws could have nice works, but they cannot be used everywhere or every time due to their high expense and large bulk. Yet small hand saws which are more flexible could cater to our needs generally in our daily life. Unfortunately when we saw a curve, the works became inconvenient and tough by using the flat saw blade. The new saw blade has surfaces with gradual changes that mid part is flat face and transform to ends' cambered surfaces in opposite directions. Thus we can get a perfect line that consists of beelines or curves easily and convenient by using it's different parts.