[After Effects]-Create snake like animation using Puppet Tool

I'm using expression because I prefer everything to be easily fixable.
You don't have to use expression. You could create keyframe animation for each Puppet Pin instead.

expression to "Puppet Pin 3"(bottom part of the shape)
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x=thisComp.layer("ExpressionController").effect("amp")("Slider")*Math.cos(time*thisComp.layer("ExpressionController").effect("freq")("Slider"));
y=effect("Puppet").arap.mesh("Mesh 1").deform("Puppet Pin 3").position[1];
[effect("Puppet").arap.mesh("Mesh 1").deform("Puppet Pin 3").position[0]+x,y];
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expression to "Puppet Pin 1"(top part of the shape)
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x=thisComp.layer("ExpressionController").effect("amp")("Slider")*Math.sin(time*thisComp.layer("ExpressionController").effect("freq")("Slider"));
y=effect("Puppet").arap.mesh("Mesh 1").deform("Puppet Pin 1").position[1];
[effect("Puppet").arap.mesh("Mesh 1").deform("Puppet Pin 1").position[0]+x,y];
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