Spinning dice

 

The picture on the left is the 3D reconstruction of a simple device I made long time ago. Unfortunately I lost it and never made another one, so I created this 3D model to show how it worked.

To make one yourself, take two dice, drill a hole in both and make them turn freely around a stick (or a cord).

Mark the left die faces with 3,4,4,4 dots and the right die faces with 3,4,4,5 dots.

To cast a line, spin the two dice in opposite directions for as long as you feel appropriate and when you stop them, add the dots. You'll get 6, 7, 8 or 9 with yarrow stalks probabilities.