-- Double Helix
-- Tsuyoshi Yamamoto
my_model(x[3], a[1])
{
PI=3.14;

cyl1=3^2-(x[1])^2-(x[3])^2;

theta=x[2];
twis1=2^2-((cos(theta)*(x[1])-sin(theta)*x[3])-3)^2-(sin(theta)*(x[1])+cos(theta)*x[3])^2;
spi1 = twis1&cyl1;

theta=x[2]+PI;
twis2=2^2-((cos(theta)*(x[1])-sin(theta)*x[3])-3)^2-(sin(theta)*(x[1])+cos(theta)*x[3])^2;
spi2 = twis2&cyl1;

sph1=64-x[1]^2-x[2]^2-x[3]^2;
sph2=49-x[1]^2-x[2]^2-x[3]^2;

theta=x[2];
twis3=64-(cos(theta)*x[1]-sin(theta)*x[3]-7)^2-(sin(theta)*x[1]+cos(theta)*x[3])^2-X[2]^2;
spi3=(twis3&sph1)\sph2;

theta=x[2]+PI;
twis4=64-(cos(theta)*x[1]-sin(theta)*x[3]-7)^2-(sin(theta)*x[1]+cos(theta)*x[3])^2-X[2]^2;
spi4=(twis4&sph1)\sph2;

spi5=spi3|spi4;
spi6=(spi1|spi2)\sph2;
my_model = spi5|spi6;
}