flat 2d plotter for 28BYJ stepper motors

Based on https://www.thingiverse.com/thing:187339
but uses stepper motors (http://anleitung.joy-it.net/?goods=dc-5v-stepper-motor-28byj-48) instead of servos and has holders for endstops (MSH-1: https://www.berrybase.de/bauelemente/schalter-taster/mikroschalter-taster/mikroschalter-mit-hebel-printmontage-1a/250vac-on-40-on-41-1-stellig?c=86). So it can calibrate itself. No screws are needed but recommended.