Tag Archives: Anti-symmetrical prime numbers

Symmetry of Broken Plastic Table Tennis Balls – in Structure, Time and Space.

First broken Plastic table tennis ball.

First of two plastic table tennis balls broken during a match on 25 July 2017.  Manufactured by XuShaofa Sports in China, whose badge is fully shown on the separate piece .  Photo by Mick Burton, continuous line artist.

This match ball is made of plastic and my table tennis club in Leeds has used the XuShaofa ball for over two years since plastic balls were introduced internationally in place of the celluloid ball. This is my favourite type of new ball to play with and they are long lasting and I have rarely seen one break.

Last night I played a Leeds Summer League match at Moor Allerton Sports and Social Centre and the above ball was broken during a game between Kiran Babra of Leeds YMCA A and Liang Wong of Leeds Judean C team.  Kiran has an outstanding vicious forehand topspin stroke which he can play from anywhere, often from wide on his backhand side of the table.

In one point he hit the ball with the top edge of his bat and it flew up and hit the corner of the lighting casing on the ceiling.  When Liang picked up the ball from the floor it was in two pieces, as shown in the photo above.   Unlike the old celluloid balls, which had a seam around the ball, this plastic ball is seamless and so when it breaks a piece usually separates.

I noticed that the piece which came off nicely encompassed the maker’s badge, along with a dent from impact, and so I pocketed it as a natural artistic object for my collection and then produced my last new ball to continue the match.

Two points after the above incident, Kiran again went for his topspin and mishit the ball in exactly the same way and it flew up and hit the corner of the lighting casing again.  This time the ball was picked up and they played another point.  (see later note at end of this post).

Things did not seem to be quite right in this point and Michael Chang said “Can’t you see that the ball is dead”.  We looked at the ball and there was a big hole in it and a loose piece inside.  I announced that this time you could look through the hole and see the reverse of the XuShaofa badge at the opposite side.

Second broken plastic table tennis ball.

Second of two plastic table tennis balls broken during a match on 25 July 2017.   Manufactured by XuShaofa Sports in China, whose badge in reverse can be seen through the hole.  Photo by Mick Burton, continuous line artist.

Another specimen for my collection.   In fact in over two years I have only seen 2 or 3 balls XuShaofa balls break and each time commented that the broken ball was “A collector’s item”.  But these two balls are something else!  Think about the probabilities of the same mishit, followed by the same trajectory and point of impact and with the speed and distance involved resulting in the same type of break.  Think about the spin, all those revolutions per second, and the first point of impact being directly on the badge and then the impact on the second ball directly opposite that of the first.

I love symmetries, but have difficulty in working out what this is.  A piece of ball with the full badge on it and a similar hole in the other ball where you can look through and see the reverse of the badge on the other side.  Is that a reflection, a transformation, anti-symmetrical, or what?

Regarding probabilities, there is probably more chance that I will post pictures of symmetrical and anti-symmetrical prime numbers on this web site than the above happening again.

Just to put the old celluloid balls to bed, XuShaofa themselves welcomed the decision to ban them saying that “celluloid is flammable and has killed countless factory workers in China from fast-spreading fires”.  I have long known of this flammable nature and have often used broken celluloid balls as fire lighters at home.

If you would like to know what was in use before celluloid balls were introduced in 1901, one original choice was the ball shape cut from champagne corks which were hit around on dining tables with cigar box lids.   No surprise that Boris Johnson could refer to “Whiff  Whaff” when welcoming the 2012 Olympics to London.

Subsequently, Battledore bats were manufactured from around 1890.  These had parchment paper stretched around a frame and I am lucky to have one circa 1903, see below.  It has “PING PONG” stamped on it, which was in general use before  J. Jaques & Sons Ltd registered the name as a copyright in 1901.  

IMG_1905 - Battledore circa 1903

Table Tennis battledore, parchment paper stretched around a frame, stamped “PING PONG” circa 1903.  Photo Mick Burton, continuous line artist.

IMG_1905 - Ping Pong

“PING PONG” stamped on Table Tennis battledore, circa 1903.   Photo Mick Burton, continuous line artist.

Pimpled rubber was first used on bats in 1903.  Mr E. C. Goode from London was in his local chemist’s when he saw a pimpled rubber mat on the counter.  He purchased it and stuck it to his plain wood table tennis bat and found it produced fast spin on the ball.  He became Champion of England and others copied his idea.

I have never used my battledore for fear that a modern ball, such as XuShaofa, might burst through the parchment.   I don’t want a ball shaped hole in that !

NOTE ADDED on 15.6.2018.  A couple of days ago I bumped into Kiran, who had broken these two balls, and he had heard that he was on my website and I told him where to find the post.  I re-read it myself and realised that things had moved on since I wrote the post.

Kiran became well known after that for breaking balls in most matches that he played in. His topspin action is extreme in that the bat travels very fast past the ball, hardly touching it, and a slight error can mean the ball hits the top of the bat and smashes.  My original assumption that the ball hitting the light casing after Kiran hit the ball was incorrect.

Other players are also finding this happens to them.  In fact a player did it twice in a match I played in this week, and Kiran said that he had done it five times in practice the night before I spoke to him.  I would rather not say how much a ball costs!