To run dbn code go here.
A quick guide to the syntax and commands is here.



// bars
paper 50
repeat a 0 1000
{
  repeat ton 0 50
  {
    set x <mouse 1>
    set y <mouse 2>
    pen ton
    line (x-13) (y-1) (x+13) (y-1)
    line (x-13) y (x+13) y
    line (x-13) (y+1) (x+13) (y+1)
  }
  repeat ton 50 100
  {
    set x <mouse 1>
    set y <mouse 2>
    pen ton
    line (x+1) (y-13) (x+1) (y+13)
    line x (y-13) x (y+13)
    line (x-1) (y-13) (x-1) (y+13)
  }
  repeat ton 100 50
  {
    set x <mouse 1>
    set y <mouse 2>
    pen ton
    line (x+1) (y-13) (x+1) (y+13)
    line x (y-13) x (y+13)
    line (x-1) (y-13) (x-1) (y+13)
  }
  repeat ton 50 0
  {
    set x <mouse 1>
    set y <mouse 2>
    pen ton
    line (x-13) (y-1) (x+13) (y-1)
    line (x-13) y (x+13) y
    line (x-13) (y+1) (x+13) (y+1)
  }
}
repeat x 0 100
{
  pen x
  line x 0 x 100
}
forever
{
  set y <mouse 1>
  set x <mouse 2>
  pen oldx
  line oldx 0 oldx 100
  pen y
  line x 0 x 100
  set oldx x
}
// funny face
// (inspired by Clifford Pickover's
// "Computers, Pattern, Chaos and Beauty", chapter 4)
load dbngraphics.dbn
// eyes
circle 40 60 5 100
circle 60 60 5 100
// nose
circle 50 45 2 100
// mouth
line 45 30 55 30
forever
{
  set x (<mouse 1>/5)
  set y (<mouse 2>/10)
  // mouth
  pen 0
  line 30 (20+oldx) 45 30
  line 55 30 70 (20+oldx)
  pen 100
  line 30 (20+x) 45 30
  line 55 30 70 (20+x)
  set oldx x
  // eyebrows
  pen 0
  line 35 (70+oldy) 45 75
  line 65 (70+oldy) 55 75
  pen 100
  line 35 (70+y) 45 75
  line 65 (70+y) 55 75
  set oldy y
}