G00X40.0Z2.0;
X0;
#1=35.0;
WHILE[#1GE0]DO1;
#2=15.0*SQRT[1.0-#1*#1/1225];
G01X[#2*2] Z[#1-35]F0.2;
#1=#1-0.5;
END1;
G00X100.0 Z100.0;