W2 (Angle starter) determines the start point of the angle, It may
be moved from left to right with the variable W2 (Width2) within possible limits
W3 represents the width of the slope.
Each radius RAD [1] & RAD [2] may be redefined.
Image below
represents default "S" radius (D-D2)/2:
When SD1 (Shelf Depth 1) is different from SD2 (Shelf Depth 2), 20-20 uses only SD2 and repeats front curve (behind frame).