G03 X0 Y0 I15 J0 Z50 K5
X0 Y0 is the point to rotate to. (also start point)
I15 J0 is the centre point (incremental from start point)
Z50 is the Z end depth.
K5 is distance between the rotations.
With this combination the rotations need to be 360deg. (50/5 = 10 rotations.)