Simple logic/oscilloscopic probe for electronic circuits in a highlighter case.
Article (in Russian) about it: https://radiokot.ru/artfiles/6639/
Article in Engish: https://www.hackster.io/iliasam/uprobe-simple-logic-probe-834bf3
See Wiki: https://github.com/iliasam/uProbe/wiki for more information.
See this video: https://youtu.be/MtbWYYT8b84