Experiment with cards as building elements

In my Pinterest-searching for projects to build for my grandson, who will be two in February, I came across this idea for using slotted cards as construction elements. So I spent too many hours cutting out a dozen cards from slotted cardboard with a bandsaw (why didn't I just make two?), then gessoing and painting. After painting one side red and one side blue, I glued in a two inch square print of the metapattern recognition design I made for him to tune in his vision system, and which he has been mildly obsessed with, to my immense satisfaction, of course.

Cardboard versions were gross failures. I learned that there is a fine difference between making the slots too tight for toddler fingers to manipulate and making the slots so loose that structures won't hold together. I regret not photographing the sagging tower.

So I turned to my friend Fabrice, who also has grandchildren, and who also has a laser cutter. Using 1/8th inch plywood, the laser cutter  enabled him to quickly produce a number of prototypes with different width slots. We finally settled on a slot that wasn't too hard to fit together and tight enough to keep structures from wobbling.

So I gessoed and painted a dozen, finished with beeswax & carnauba, and fit them together. When I take the structure apart, I'll find out how/if I damaged the metapatterns. Meanwhile, it is still beyond his current fine motor skills, so I'll set the pack aside until he's ready. Like working on an electronic circuit for a while, then throwing the switch and seeing the lights flash, it will be worth it if he takes to the cards. He is never disingenuous about whether or not he likes one of my experiements.