The leg to apron design is simple - a mortise on both ends of each apron part, corresponding mortises on two faces of each leg. The front of the apron is stepped back about 1/4" and the mortises in the aprons are "cheated" towards the front to allow for a groove on the back for a Z-clip to hold the top onto the apron/ legs.
The "step back" could complicate things a bit, as would the "cheat towards the front of the apron". The DOMINO simplified things significantly.
The best part is - NO LAYOUT LINES and the absolute minimum set up time.
I hope the stuff at the following url conveys just one example of the value of the DOMINO to furniture making - at least at the hobbiest / amateur/ one man shop level.
This is getting interestinger and interestinger.
More to come.