more realistic demonstration, it takes a single round pcb design like img1, and according to lots of options (x, y, padding, radius) turns it into a panel as seen in img2
My Kicad panelizer is now available as a very nice website where you can just copy-paste the kicad board you want to panelize, set the options, and get the panel back https://panelizer.dev.cthu.lu/
and like.. it's *really* easy to use, surprised myself with that because normally adding mousebites and precisely connecting edgecut segments is a paaain
example of a panel that was done like this (but by hand, which sucks)