Fig. 1. Hovering motions studied in this paper. (A) The chord position (solid line with a black circle) and the coordinates, (B) generic asymmetric strokes along an inclined stroke plane, (C) normal hovering along a parabolic stroke plane and (D) normal hovering along a figure of eight. The strokes in C and D can be decomposed into pairs of asymmetric strokes described in B. The numbers next to the chords indicate the time sequence and also identify the corresponding segments in the decomposition.