// Draw Fractal Tree in Frink

// Define the tree function
FractalTree[x1, y1, angleval, lengthval, graphicsobject] :=
{
   if lengthval > 1
   {
      // Define current line end points (x2 and y2)
      x2 = x1 + ((cos[angleval degrees]) * lengthval)
      y2 = y1 + ((sin[angleval degrees]) * lengthval)
      // Draw line - notice that graphicsobject is the graphics object passed into the function.
      graphicsobject.line[x1,y1,x2,y2]

      // Calculate branches. You can change the lengthval multiplier factor and angleval summand to create different trees
      FractalTree[x2, y2, angleval - 20, lengthval * 0.7, graphicsobject]
      FractalTree[x2, y2, angleval + 20, lengthval * 0.7, graphicsobject]
   }
}

// Create graphics object
g = new graphics

// Start the recursive function. In Frink, a -90° angle moves from the bottom of the screen to the top.
FractalTree[0, 0, -90, 30, g]

// Show the final tree
g.show[]