tclinit {
  global t
  set t 0

  toplevel .slfwin.slider

  scale .slfwin.slider.scale -from 0 -to 1 -resolution 0.01 -tickint 0.25 -length 400 -orient horizontal -variable t
  pack .slfwin.slider.scale -side top -fill x

  proc Spiral { x y b } {
    global t

    #The b argument tells us if this is the x or y coordinate
    #0 means x, 1 means y

    set nx [expr $x - 0.5]
    set ny [expr $y - 0.5]
    set c  [expr cos(6.28*$t)]
    set s  [expr sin(6.28*$t)]

    if {$b==0} {
      set r [expr ($nx * $c - $ny * $s)]
    } else {
      set r [expr ($nx * $s + $ny * $c)]
    }
    return  [expr $r + 0.5]
  }
}
point pFILE1 ( {Spiral 0.475 0.608 0} {Spiral 0.475 0.608 1} 0.000 )
endpoint
point pFILE2 ( {Spiral 0.382 0.485 0} {Spiral 0.382 0.485 1} 0.000 )
endpoint
point pFILE3 ( {Spiral 0.565 0.490 0} {Spiral 0.565 0.490 1} 0.000 )
endpoint
face fFILE1 ( pFILE1 pFILE2 pFILE3 )
endface
object oFILE0 ( fFILE1 )
  solid SLF_HOLLOW
  shading SLF_WIRE
endobject
camera cam
  projection SLF_PARALLEL
  frustum ( -0.5 -0.5 -2 )
          ( 0.5 0.5 -0.01 )
endcamera
group gCam
  instance cam
   id iCam
   translate ( 0.5 0.5 1 )
  endinstance
endgroup

window win
endwindow

viewport vp win
endviewport

render vp gCam.iCam.cam oFILE0
endrender