Ropes and cables between fixed points, solved from the equations and published with everything needed to run them again.
| study | question |
|---|---|
how-hard-a-washing-line-pulls/ |
Eight garments on a six metre line: as the slack comes out, how large does the horizontal pull on the posts get compared with the weight of the washing itself? |
when-a-power-line-heats-up/ |
Four identical power lines strung tight to slack all warm from 15 to 55 °C: which one gains the most sag? |
Each study folder holds its solver, a frozen reference of every reported number with the SHA-256
of the modules that produced it, and a reproduce.py that re-solves the registered cases and
stops with an error if anything has moved.
pip install -r requirements.txt
cd how-hard-a-washing-line-pulls
python reproduce.py --quick
The controls ship with the solver, and they are the reason the numbers are believable: the first solver written for this rig returned zero horizontal pull for every case, and the second returned a full table of plausible values taken from states it had never converged. Neither was caught by reading the code.