Twos and threes are NOT master builders. There may be a few who can build in each class, but most of them just mess around with the materials. That's a good thing, at it helps them to learn, but occasionally it's nice for them to see progress.
These large No Ends are just the ticket. This was the first time we've used them with the young threes class. I set up the base as a small cube so they could see what the potential was and the kids added the rest. For many of them it was about getting a little proprioceptive input as they pushed the rods into the connectors, with no notice of the result.
I provided different swaths of fabric to cover the structure with, but nobody wanted to cover it, even with see-through tulle.
Since these building toys are plastic (recyclable, apparently) they can be used outside and hosed off. We usually use them in our large motor room, but on this day I brought them into our classroom because it was stormy outside.
The link above is where you can buy them. For more information on No Ends, visit the No Ends website.