.
Today we use such zig zag orientation tools: 

 "left, ahead, right, right, eastwards...".

Just one left/right or east/west confusion would disturb this route

The ZZ navigation describes the same route with quantifed directions acc. to the convention for imaginary clocks:

m12 = from my body to north. 

According to the picture right hand, a ZZ-route would look like this:

"m4 m7 m11 m9 m7 m12 ..."

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