true for clockwise arcs (G2), false for counter-clockwise arcs (G3)
OptionaliX offset from the start point to the arc center (I/J mode)
OptionaljY offset from the start point to the arc center (I/J mode)
OptionalrArc radius (R mode); takes precedence over i/j when non-zero
OptionalxAbsolute target coordinates; an omitted axis keeps its start value
OptionalyOptionalz
Describes a G2/G3 arc move relative to a known start position