Check out pages '2' and '3' too for the full picture.
Note the drawings below include the original MT137 and below it, how to construct MT 137 taken from the web site linked above, and if you have read the above link you will know that I have always worked on the assumption that there were five mechanisms. There are several supporting clues which also point to the same number.
Splitting the drawings into five parts reveals some information. In each division in 'A', you can see, drawn vertically, two uprights surmounted by a single one.. They bear a striking resemblance to the figures labelled 'C' and 'D', which are shown horizontally. But why two 'C' and 'D's? I think only one hammer is needed in 'C' plus the parallel rods. The same in 'D' but the hammer used is rotated around the other way to point outwards or to the left.
The item marked 'E' is the storks-bill, lazy tongs, scissor jacks or whatever you prefer to call them. Item '5' is a spinning top, just in case no one makes the connection that this is all about a rotating device. I won't explain item 'B' as it would require too much extra explanation here, but obviously it has a connection with item 'A'. But I will show its meaning later this year, when I've checked a couple of things out first.
Lastly the text is hard to read at item '5' but variously it has been translated as:-
"The children play heavily on the little pillars with loud little clubs."
"The children play loudly on the little pillars with heavy little clubs."
and finally something completely difference as included in my version of MT:-
" 5. Children's game in which there is something extraordinary for anyone who knows how to apply them in a different way."
The reason for this difference is due to the ambiguity of the handwriting. Mike, my translator had several goes at it and came to the conclusion that his version was right, but who knows?