$e \implies$ [-1,1,3,4,6,7,8,9,10,11,16,18,20,24,26,27,31,33,37,39,41,42,43,45,46,48,51,53,55,58,59,61,63,65,67,68,69,70,71,72,74,75,76,80,82,84,85,89,97,100,101,102,105,106,107,108,110,113,114,115,116,119,120,121,122,126]
Common digits places with value 1 between $\pi$ and $e$ in binary expansion:
[-1,3,6,11,16,18,33,41,43,48,53,58,63,68,71,72,76,80,85,106,107,108,114,115,116,119,120,122,126]*2
($*$2 means each element is actually duplicated. Alternately, think about adding two identical lists together)
[-1,3,6,11,16,18,33,41,43,48,53,58,63,68,71,72,76,80,85,106,107,108,114,115,116,119,120,122,126]*2 = [-2,2,5,10,15,17,32,40,42,47,52,57,62,67,70,71,75,79,84,105,106,107,113,114,115,118,119,121,125]
So you see, the lists of common digits is that they all get shifted to the left by 1 unit
Now we can compare this with the digits in the $\pi, e$ that are not taken cared of, i.e.
$\pi$ remaining [0,12,13,14,15,19,21,23,25,29,38,40,47,57,60,64,77,81,87,91,93,94,95,103,104]
$e$ remaining [1,4,7,8,9,10,20,24,26,27,31,37,39,42,45,46,51,55,59,61,65,67,69,70,74,75,82,84,89,97,100,101,102,105,110,113,121]
Commons[-2,2,5,10,15,17,32,40,42,47,52,57,62,67,70,71,75,79,84,105,106,107,113,114,115,118,119,121,125]
Common in both $e$ and Commons:
[10,42,67,70,75,84,105,113,121]*2
e remaining [1,4,7,8,9,20,24,26,27,31,37,39,45,46,51,55,59,61,65,69,74,82,89,97,100,101,102,110]
[-2,2,5,15,17,32,40,47,52,57,62,71,79,106,107,114,115,118,119,125]
Common in both $\pi$ and Commons remaining
[-2,2,5,17,32,52,62,71,79,106,107,114,115,118,119,125]
$\pi$ remaining [0,12,13,14,19,21,23,25,29,38,60,64,77,81,87,91,93,94,95,103,104]
[10,42,67,70,75,84,105,113,121]*2 = [9,41,66,69,74,83,104,112,120]
[15,40,47,57]*2 = [14,39,46,56]
Further increments after another series of commons are taken account of:
[9,41,66,69,74,83,104,112,120] => [8,41,66,68,73,83,103,112,120]
[14,39,46,56] => [13,38,45,56]
$\pi$ remaining [0,12,13,19,21,23,25,29,38,60,64,77,81,87,91,93,94,95,103]
$e$ remaining [1,4,7,8,20,24,26,27,31,37,45,51,55,59,61,65,82,89,97,100,101,102,110]
Commons remaining [-2,2,5,17,32,52,62,71,79,106,107,114,115,118,119,125]
[6,41,66,68,73,83,103,112,120]
[0,19,21,23,25,29,60,64,77,81,87,91,93,94,95,103]
[1,4,20,24,26,27,31,51,55,59,61,65,82,89,97,100,101,102,110]
[-2,2,5,17,32,52,62,71,79,106,107,114,115,118,119,125]
There are no carryovers remained, thus the sum is done
Now, as you may have noticed, during this whole iteration, usually the carryovers in each step tend to be eaten up by $e$ instead of $\pi$