01  function ellipse_conjugate( va, vb, ua, ub )
02    dim u: u = vector_create( ua, ub )
03    dim v: v = vector_create( va, vb )
04    dim n: n = vector_cross( u, v )
05    dim w: w = vector_cross( v, n )
06    dim c: c = vertex_middle( va, vb )
07    dim h: h = vector_length( v ) / 2.0
08    dim r: r = vertex_translate( c, vector_rescale( w, h ) )
09    dim m: m = vertex_middle( ub, r )
10    dim s: s = vector_create( ub, r )
11    dim g: g = vertex_length( c, m )
12    dim p: p = vertex_translate( m, vector_rescale( s, g ) )
13    dim q: q = vertex_translate( m, vector_rescale( s,-g ) )
14    dim o: o = vertex_middle( c, ub )
15    dim i: i = vertex_length( c, vertex_translate( o, vector_create( p, o ) ) )
16    dim j: j = vertex_length( c, vertex_translate( o, vector_create( q, o ) ) )
17    ellipse_conjugate = array( c, _
18      vector_rescale( vector_create( c, q ), i ), _
19      vector_rescale( vector_create( c, p ), j )  _
20    )
21  end function