Japanese need square holes to put their square watermelons
So this drill is invented.
http://www.youtube.com/watch?v=RqktRZ9t1GM

Now all we need is square screws!

Wow, amazing accuracy and precision for a drill that is rotating so fast.

It's hard to get a close look at the holes in this vid but it looks like there may still be small radiuses in each corner, so not a true "square" hole

This is awesome! Some fine engineering here.

There's just no pleasing some people. (#4)

#4 there are, but the rest of the edges are perfectly straight. And no real corner is really infinitely sharp and neither are square bars that go in these holes.

Anyway, this defies common sense, so it qualifies as awesome!

Check out this interactive demonstration.
http://demonstrations.wolfram.com/SquareHoleDrillInThreeDimensions/

Minecraft

Its not a drill as its starting with a pre drilled 10mm round hole.

Also these days they can cut square holes in metal in a fraction of the time with high power laser cutters.

Amazing but Still am not convinced its a perfect corner

This is how japaneese people make icecube trays

Nothing new. I was tought how to use one of these in my apprenticeship in 1980. It's still amazing to watch.

#1 & #10 This vid is Chinese,not Japanese ,and the technique has been around in the US for decades. I think this is an old video.

#12: If this video is Chinese, why is it in Japanese? Chinese written language has no curly characters. The Japanese however use traditional Chinese characters alongside with their own alphabet.

Yep PowerRangers, thats all!