I bought this 4D puzzle of a chambered nautilus when we traveled at Christmas because it looked like a really cool puzzle that we could talk some science around. Molly found it the other day and spent an entire morning putting it together. It took her so long because JohnJohn grabbed the box with the diagram and instructions on it and hid it. Plus, none of us really knew what a chambered nautilus was and so it was hard to imagine it in any D, nonetheless 4D. She proudly put it on our bookshelf when she was finished.
The next day I found Joseph at the table drawing a picture of it.
Yesterday, as I went to put a pan away, I found the box. I also found a toothbrush, a boot we lost in November, and a size 1 diaper (we are currently in size 3) as I cleaned out the cabinet.
This toy has kept us all very busy.