参考答案

图(a)：
%
00012
N10 G54 G00 X0 Y0
N20 M03 S900
N30 G41 X-22.0 D01 M08
N40 G01 X-24.0 F50
N50 G02 X-40.0 R8.0
N60 X0 Y40.0 R40.0
N70 Y24.0 R8.0
N80 X-24.0 Y0 R24.0
N90 G00 G40 X0 M09
N100 M05
N110 M30
%
图(b)：
%
00013
N10 G54 G00 X70.0 Y20.0
N20 M03 S900
N30 G42 X45.0 Y23.0 D01 M08
N40 G01 X42.5 Y9.68 F50
N50 X5.0 Y19.37
N60 G03 Y-19.37 R-20.0
N70 G01 X42.5 Y-9.68
N80 G03 Y9.68 R10.0
N90 G00 G40 X70.0 Y20.0 M09
N100 M05
N110 M30
%
图(C)：
%
00014
N10 G54 G00 X70.0 Y20.0
N20 M03 S900
N30 G42 X39.0 Y0 D01 M08
N40 G01 X13.08 F60
N50 G02 X8.41 Y3.21 R5.0
N60 G03 X0 Y-9.0 R-9.0
N70 G01 X23.92
N80 G02 X28.59 Y-12.21 R5.0
N90 G03 X37.0 Y0 R-9.0
N100 G00 G40 X70.0 Y20.0 M09
N110 M05
N120 M30
%