Five people just taught an AI the lesson every junior banker learns by getting screamed at, and now it builds board decks for 13 cents a pop. Claude Fable 5 charges $8.19 for the same job, and it scored lower on their test. The startup is Paper Instruments, and the whole thing cost them about $300K. To see why that's a big deal, you have to know why AI got good at coding before it got good at anything else in an office. Code either runs or it doesn't. A lab can have a model try a problem…