constant c_inverse_squares
constant c_springs
constant c_gravity
constant c_dampening

foreach (node n1)
  foreach (node n2)

    force = (0, 0)

    if (n1 != n2)

      force += inverse_squares (n1, n2)
      force += gravity (n1, n2)

      if (n1 isconnectedto n2)
        force += hookelaw (n1, n2)
      endif

    endif

    n1.velocity += force
    n1.velocity *= c_dampening

  end
end
for nodes { position += node.velocity}