1. Use px:
Px is the radius of the circle size value into this div with rounded corners cut up div
2. Use%:
If the length and width as the length of the radius of the circle is the result obtained by this percentage
If the effect is not the same length and width is generated by multiplying the percentage of the width and height obtained r1 and r2, the radius of curvature is depicted as two ellipse ellipse produced by cutting to
