One advantage of a drawing machine working with coordinates is that it does not need to see what it draws.
Under the blue light
I bought a fountain pen with a refillable cartridge, and some UV ink.
The UV ink is invisible to the naked eye but the pen did leave trails on the paper.
Someone in Brazil drew this on Mandalagaba years ago and I’ve used it to stress test plotters since :). I wish I could get in touch to show them.
I’ve gotten pretty good at producing these.
The best part is always watching them being drawn
