Yeah that should work, but the second wall is a bit different. I think I maybe made it a little too unclear. Here's a hint and answer for the second wall in case you want them (reversed so people in the comments don't get accidentally spoiled):
Hint: eton a gniyalp naht rehto gnihtemos setacidni hctawpots eht eno dnoces eht rof
Answer: ti ot txen epahs eht no sedis eht ot lauqe sdnoces fo tnuoma na rof gnitiaw setacidni hctawpots eht
If it's the first wall I'm not sure, maybe try counting the shape sides once more. Should be "owt eno eerht evif ruof eerht owt" (reversed again)
OH MY GOD... I'm dying. I've been doing this the entire time and opening up the tunnel but I couldn't see it. I ended up screenshotting the game and putting it into krita, overlaying white to brighten it like five times. Dim monitors are the bane of my existence. Pour one out for us idiots with poor vision. You don't know want to know how long I struggled with this