In the dfns docs and other places, there are wonderful diagrams, arrows and elaborate boxes -- are they painstakingly hand-edited, or is there a tool in play?

I imagine they were hand-edited.

You mean the line drawing character ones?

Dfns workspace has some tools that could help. When stencil was just added, I wrote a program to convert ASCII diagrams to line drawing chars…

@Adám yes

Right, so I imagine they are a mixture of generated and hand-drawn. Note that the APL keyboard layer on Linux has line drawing characters directly accessible in a sensible layout:

├────┼────┼────┼
│    │    │    │
│7 ┌ │8 ┬ │9 ┐ │
├────┼────┼────┤
│    │    │    │
│4 ├ │5 ┼ │6 ┤ │
├────┼────┼────┼
│    │    │    │
│1 └ │2 ┴ │3 ┘ │
├────┴────┼────┤
│         │    │
│0 ─      │. │ │
└─────────┴────┴

For the reader: My Windows AltGr layouts have this too, as AltGr+Shift+S, followed by those keys.

@Adám ohh til

And the last solution for problem 7 is also realy nice. We should have thought about that last friday. You had probably a good sleep/ red bull/ or cup of coffee.

@Richard Why?

@Adám it should give a 1 or 0 as an answer.

The final ∧/ only works if you ravel the previous result

If I am not mistaken

Oh wow, that's terrible. I'm missing a ⊃

or (I am always confused with this problem) at least one vector should have to '1''s and must be tested for that

yes

The code on GitHub has it correct: H←{∧/4≠|⊃+/,×⍺∘.-⍵}

Maybe I'll re-record

What ever doesn't take to much time. Our next problem is not to complicated

Maybe I can fake the log, and simply append a video snippet.

@xpqz great list!

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