MM STD Tutorial Part 6

Here's the diagram we had at the end of Part 5. Notice that not all of the states have arrows between them. Of course, we can't have an arrow going from a state ending in r to a state ending in r, or from a state ending in l to a state ending in l, because we always alternate hands. But what about Lr and Ll? Should we have arrows between them?

The states Lr and Ll correspond to the arms being crossed, left over right, and if we are to have arrows between them then it would imply that you can juggle with your arms crossed. Well, of course you can. What about inside versus outside exchanges? When most people juggle with crossed arms they do inside exchanges, resulting in a pattern that looks like a reverse cascade. That may require some thought - it's not immediately obvious.

It is, however, possible to do either inside or outside exchanges with the arms crossed, and this is true for either right arm over or left arm over. This now gives us this diagram. But what about the other "missing" arrows? Should there be an I arrow from Ur to Rl for example? Or perhaps an O arrow from Rl to Ur?

To answer this question, let's look closely at the possibility of doing an inside exchange from Ur to Rl.

Firstly, this means that you start with the arms uncrossed and do an inside exchange with the right hand. This will happen more-or-less on the right hand side of the body, so the right hand throws from around the centre of Juggle Space, moves further to the right, and catches. If this is done in the most fluid and natural way, this results in the arms being even more uncrossed (if that makes any sense) than when they started. In particular, the most fluid and natural movements certainly do not result in the arms being crossed. This possible transition is therefore not included in the diagram.

The same is true of all the other missing arrows. They are all excluded from the diagram because the movements they represent do not feel natural. This does not mean that they are impossible or uninteresting. It just means that they are, in some sense, for the moment, less desirable.

So here is the final version. Any arrows missing from this are omitted not so much because they are impossible, but because they are somewhat less desirable.

The next few lessons will cover using the diagram to analyse existing patterns, as well as how to overcome the various shortcomings.

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MM STD 07

Quotation from Tim Berners-Lee