| 
 Experimenting with purpose-made apparatus |  | 
| A current with a steady pattern. | A current that changes periodically. | An irregular current. | ||||||
|  |  |  | 
|   | Depending on the conditions, irregular currents also occur. | 
Experimental conditions
Water depth : 2.5 cm
Filming conditions
Speeded up 6 times.
240x180:15fps, 320x180:30fps.