About Juno's Spinner 1  
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Condition of elements  
Juno's Spinner is composed of elastic elements.Those are jointed by a metal eyelet,and can move freely around the joint. Right figure is a cube type Juno's Spinner. 

We consider Juno's Spinner to ,fourbar linkage mechanism of elements.  
If we fix A,bar B C can rotate but rotation angle is not always equal.However if fourbar linkage mechanisim is parallelogram,B and C rotate same angle.  
Let planar fourbar linkage mechanisims closes around element A.When element A is fixed what is the conditon element B,C,,,G can move. Most simple condition is quadrilateral 1,2,,,6 are all parallelogram. 

Many Juno's Spinner satisfy this parallel conditon but because of elasticity of element, this is not always needed condition. 
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