Stefan Mileschin

As conductive ink becomes readily available and in greater varieties, we’re starting to see some intriguing applications. [Marion Pinaffo] and [Raphaël Pluviange] created a book of papercraft projects that employ silver-based ink for making a circuit’s wires, carbon-based ink for resistance, as well as color-changing ink. Electronics components’ leads are slipped into slits cut into the paper, connected to conductive-ink traces.

[Marion] and [Raphaël] use 555s, ATtiny85s, watch batteries, and other hardware to make each activity or project unique. A number of projects use a rolling ball bearing to make beeps in a piezo speaker. They also created beautifully designed pages to go with the electronics.
http://hackaday.com/2017/07/27/play-...activity-book/