A few years ago, the Japanese educational theorist Fumia Kayo discovered that nursery-school children were obsessed with creating hikaru dorodango — balls of mud polished to such smoothness that they shine. Kayo started using an electron microscope to figure out precisely how mud could be made to shine best, and, as Web Japan reports, came up with the following technique:

1. Pack some mud into your hand, and squeeze out the water while forming a sphere.

2. Add some dry dirt to the outside and continue to gently shape the mud into a sphere.

3. When the mass dries, pack it solid with your hands, and rub the surface until a smooth film begins to appear.

4. Rub your hands against the ground, patting and rubbing the fine, powdery dirt onto the sphere. Continue this for two hours.

5. Seal the ball in a plastic bag for three or four hours. Upon removing the sphere, repeat step 4, and then once again seal the sphere in a plastic bag.

6. Remove the ball from the bag, and if it is no longer wet, polish it with a cloth until it shines.

Apparently this is now a national trend, and preschool children in Japan are busily making dorodango as we speak. Which is to say, preschool Japanese children are spending two hours polishing balls of mud! I love it.

Kayo has developed a 5-star rating system for the luster of the balls; that one pictured above rates a “4”. He’s got a “5” at home, and damned would I love to see it.

(Thanks to Ian Daly for this one!)