Yup: 36 hours on a BBC B+ micro for monochrome mandelbrot. I used to leave it running over the weekend, and tried zooming into various parts of the set over some weeks. I used to photograph the monitor, and I'm now searching for the negatives...
"(Up until 1971, British currency was expressed in pounds, shillings, and pence, with 12 pence in a shilling and 20 shillings in a pound. This makes even addition complicated, as tourists often discovered.)"
Just after I had learned to add and subtract pounds shillings and pence, they went decimal! Ha!
"(Up until 1971, British currency was expressed in pounds, shillings, and pence, with 12 pence in a shilling and 20 shillings in a pound. This makes even addition complicated, as tourists often discovered.)"
Just after I had learned to add and subtract pounds shillings and pence, they went decimal! Ha!