String figure glossary
Mitosis (Cell Division)
Invented by Martin Probert 2002. This moving figure illustrates mitosis: a single cell divides into two new cells. Construction time 15 seconds.
- Use a 0.80 metre wide loop.
- Insert the little fingers into the loop.
- Bring the right hand to the left hand, pass the right thumb away over the left little finger loop, then insert the right thumb from below up into the left little finger loop and pick up the far string of the left little finger loop on the back of the thumb.
- Insert the left thumb from above into the right thumb loop and pick up on the back of the left thumb the near string of the right thumb loop. Separate the hands. (There should now be four loops, one on each thumb and one on each little finger, and all loops except that on the right thumb should have a half twist.)
- Pass each middle finger under both strings of the thumb loop and pick up both these strings on the back of the middle finger.
- Transfer the right thumb loop to the left thumb.
- Insert the right thumb from above into the upper loop on the left thumb, then (with the right index helping) insert the right thumb from below into the lower loop on the left thumb. Remove the left thumb from the right thumb loop and separate the hands. (The strings of the right thumb loop should now pass between those of the left thumb loop.)
- Transfer the left thumb loop to the left middle finger. Touch the tip of the left index to the tip of the left middle finger and slide the upper loop off the left middle finger onto the left index.
- Transfer the right thumb loop to the right index.
- Pass each thumb away over four strings and under the two far strings of the middle finger loops, then pick up from below the near string of the little finger loop and draw the string towards you.
- Release each middle finger from all loops.
- Transfer the thumb loops to the index fingers.
- Insert each thumb from below into both loops on the index, and release the upper loop from the index. Let the released loop fall to the base of the thumb. Keep the thumb inside the remaining index loop during the first part of the next step.
- Transfer the little finger loops to the thumbs. (Each thumb should now have two loops, and in addition should still lie within the index loop.)
- Draw each thumb downwards to remove the thumb from the index loop, then pass each thumb away under the far string of the index loop. Transfer the upper thumb loops to the little fingers. Return the thumbs to the usual position on the near side of the figure.
- Point the fingers of both hands away from you to place the figure in a vertical plane. Hold each thumb against the adjacent index to prevent any movement of the thumb loop as you gently release each index loop, taking care not to separate the hands.
- A circular 'cell' is visible with several 'chromosomes' within it. Keeping the little fingers stationary in space, separate the thumbs, an action which will turn both hands increasingly palm up. As a result of this motion the 'cell' will divide into two new 'cells', each cell having the same distribution of 'chromosomes' as the original 'cell'.
- To dissolve the figure, release the thumbs and gently separate the hands.
Copyright © Martin Probert 2003
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