while the two circle pointers goes from X to B, Y to B, and both 1-CosX and 1-sinX go from zero to 0.29289.
And then in the diagonal a line goes from A to B whose distance equals 1.
Total moves equal 1 + 0.29289×2 = 1.5857864.
Phew = 180/90 × 1.5857864= 3.17157
that means 2 becomes 1.5857864. The full length of 2 gets shorted as far as 0.414213 as represented by the line in the edge’s diagonal.
So the initial length of 2 can be descripted with 1+2×0.0.29289+0.41421
There are more instances which gives the same conclusion: the ratio of 0.79289