In the beginning it was simple, like this tilt-top table/bench contraption:
It’s a convertible table/bench. The top pivots around the rear pins and is locked in down position by the front pins. It should be symmetrical and the top should be able to hinge around the front pins.
Typically, there is storage in the base.
Let’s make it more complicated.
The hinges look seriously undersized yet it exists.
Now let’s engineer it and make it more complicated and harder to produce.
This base also has storage.
Another difference is that this unit has 2X4 legs and not sides made from boards.
The only advantage of this construction I can see is that the table top sits lower in the bench position. This could be useful if you need the wall space for your art collection:
Finally, the Arts & Crafts/Mission variation of this idea:
Here, the top pivots around bolts with vertical movement provided by slots on the supports. For added stability, the “feet” on the supports rest in cups on the seat.
Many ways to achieve the same goal.