> Something you don't cover is my pet peeve with Duplo/System
> compatibility: 2x3 system bricks.
SNIP
> A few notes about Baby (Primo): it is compatible with Duplo via
> http://peeron.com/inv/parts/31007
> and Primo bricks do fit neatly onto Duplo studs (but with a
> half-Duplo-stud offset). Primo has no clutch power.
>
> There is another large brick system, Soft,
> http://guide.lugnet.com/set/?qc=dacta/legosoft
> which (IIRC) is directly compatible with Primo.
Some of the 2x4 Duplo castle pieces fit onto Quatro because their stiffening plates are set much deeper within: (URL) Duplo Brick 3 x 4 x 2 with Machiolation> The (URL) 4777 Knight's Castle> (URL) comes with> three (URL) enourmous Duplo plates> (...) (18 years ago, 26-Jul-06, to lugnet.quatro, FTX)
(...) I like it. The incompatibility of Duplo 2x4s and Quatro is not really clear from the photos. I only understood it because I've seen Quatro in person, and that was almost the first thing we observed about it. \begin{rant} Something you don't (...) (20 years ago, 14-Mar-05, to lugnet.quatro)