I may no longer have children and do not yet have grand kids (no hint here!), but that would not stop me playing with this.
From the kick starter: STRAWBEES, a simple connector system for straws or cardboard. Strawbees construction kit is based on one simple unit that lets you connect straws to each other. You stick a Strawbee into the ends of a standard quarter inch (6mm) straw to make struts and then connect them with another Strawbee.
https:
//www.kickstarter.com/projects/1624049406/strawbees-dream-big-build-bigger?ref=techdirt