Peter was sunk

Anyone know what the △ symbol in the last frame means? I've asked around, and the best guess so far is a reference to the × △ ○ ◎ grading system used in japanese schools (× wrong, △ partially correct, ○ correct, and so on).

That might be the right meaning here, but it given the context it feels a bit odd. Any better ideas?

So, I asked on pixiv and got the following response...

hema 11/8/2013 17:36
「電△＝電さんかっけー(電さんかっこいい）　三角形→さんかっけい→さんかっけー→△　 ネット上の"スラング"デース！」

...which makes a lot more sense, and fits the context better. Updated the translation accordingly.

Plasma-chan is so cool ~

SoSD said:

So, I asked on pixiv and got the following response...

hema 11/8/2013 17:36
「電△＝電さんかっけー(電さんかっこいい）　三角形→さんかっけい→さんかっけー→△　 ネット上の"スラング"デース！」

...which makes a lot more sense, and fits the context better. Updated the translation accordingly.

i know i'm 2 years late to the party but... would that qualify for the pun tag? or is it too "don't explain the joke"-y?

freecom said:

i know i'm 2 years late to the party but... would that qualify for the pun tag? or is it too "don't explain the joke"-y?

I think it wouldn't, since it's not really a pun, just net slang.