Celtic knots as Lissajous knots

4 Lissajous knots:

5-2 - three twist knot
6-1 - stevadore knot
7-4
8-21

The knot 7-4 is generated by the Lissajous function:

function f(t) =
[ cos(nx * t + px) ,
cos(ny * t + py),
cos(nz * t + pz) * vz
];

where
nx=3;
ny=2;
nz=7;
px=10; // by experiment
py=35;
pz=0;
vz=0.25; // vary to change height

The OpenSCAD code for this and other knots, including the other Lissajous knots can be generated from my knot index page:

http://kitwallace