弦を張ってないギター
strings-not-affixed guitar
guitar without strings
The spreadsheet had 弦 as “stringed instrument,” but I think here it’s just “string” (like the string of the stringed instrument)
I think the meaning for たまたま was off in the spreadsheet too - it said “occasionally,” but I think the “by chance” meaning is what was intended in this case.
“By chance, I brought a guitar without strings today” (which, ok weirdo)
Summary
On the paper it says かなしいたけ
悲しい（かなしい）+ しいたけ (like shiitake mushrooms)
I honestly laughed out loud when I understood this This comic is so my style of humor xD
Great chapter. Something about the guitar and oscilloscope group had me cracking up. I also loved もがわ先生’s speech about the tree so closely following her nihilistic rant from the last chapter.
They’re the same girls who were talking about Potapotamian culture and the liminality of divinity back in chapter one, so they’re definitely coming across to me as absurdly intellectual.
There are some things you can tell through shape and colour, but there are also some unknown things, but maybe it’s okay for some things to remain not described?
I agree with your translation of the first box, but for the second one I rather read it as „but it’s probably ok to have these unknown things“. Does this help? If not, what exactly are you struggling with?
Hmmm, but is it “ok” as in “I don’t mind if they are unknown” or is it even better if they are unknown, because it is fun to have some mysteries in life?
Oh, yep, that too. I’m just guessing that her mother’s face is the sample of an unknown thing here.
ok weirdo) 
