Robot.osl

// Diffuse Color
shader
colorByP(float minheight = 1.25,
        float maxheight = 1.25,
        color mincolor = color(1,0,0),
        color maxcolor = color(0,1,0),
    output color resultRGB = 0
)
{
    point p = transform("world", P);
    float blend = smoothstep(minheight, maxheight, p[1]);
    resultRGB = mix(mincolor, maxcolor, blend);
}

// Bump - SeExpression
length_xyz =floatInput1; #0.0,2.0
width1_xyz =floatInput2; #0.0,2.0 
width2_xyz =floatInput3; #0.0,2.0 

x1 = choose(width1_xyz/2,P[0],P[1],P[2]);
y1 = choose(width2_xyz/2,P[0],P[1],P[2]);
ss = choose(length_xyz/2,P[0],P[1],P[2]);

x = x1;
y = y1;

tt = (x > 0 && y >= 0) ? atan(y/x): 
        (x > 0 && y < 0) ? atan(y/x) + 2*PI :
        (x <0) ? atan(y/x) + PI :
        (x == 0 && y > 0) ? PI/2:
        (x == 0 && y < 0) ? 3*PI/2: 0;
tt = tt/(2*PI);

twist =floatInput4; # 1,200.00
threadCount =1.000; #1,20.00
grooveShape =3.487; #0.1,10.00  
disp = (ss*threadCount - tt*twist)%1;
disp = ((disp -.5)*2) -> abs() -> pow(grooveShape) -> invert();

disp