Generate all solvable 2xN mazes Your job is to write a program that takes a number N as input and outputs all 2-by-N mazes that are solvable.
Output format can be in the form of any two distinct values representing wall and empty - I use x and . here but you can use anything. You can have a matrix, array, string, ascii art, whatever is convenient, and it can be horizontal, as shown in my examples, or vertical.
A maze is solvable if it has a path of empty cells (represented here as .) from the left end to the right end. For example,
xxxx.....
.....x..x

is solvable, because you can trace a path (marked with O):
xxxxOOOOO
OOOOOx..x

But this is not.
xxx.x..
..xxx..

You cannot pass through diagonal gaps, so this is also not:
xxx...
...xxx

Testcases
1:

.
. 
 
.
x

x
.

2: 

..
..

..
.x

.x
..

..
x.

..
xx

x.
..

xx
..
Excel, 163 143 bytes
=LET(a,BASE(SEQUENCE(3^A1)-1,3,A1),b,FILTER(a,ISERROR(FIND(12,a))*ISERROR(FIND(21,a))),SUBSTITUTE(b,2,0)&amp;&quot;
&quot;&amp;SUBSTITUTE(SUBSTITUTE(b,1,0),2,1))

Use 1 for walls and 0 for empty cells.
Original
=LET(a,BASE(SEQUENCE(3^A1)-1,3,A1),b,FILTER(a,ISERROR(FIND(12,a))*ISERROR(FIND(21,a))),SUBSTITUTE(SUBSTITUTE(b,1,&quot;X&quot;),2,0)&amp;&quot;
&quot;&amp;SUBSTITUTE(SUBSTITUTE(b,2,&quot;X&quot;),1,0))

Uses 0 for empty cells and X for walls.
Link to Spreadsheet