Now for the sliding dovetails. The feet will be made of two boards attached at a right angle in sliding dovetails on the bottom of the corners. The point of that right angle has to cross the line of the diagonal between the two points at which the rails exit the corner.
The router table makes sliding dovetails possible (OK, feasible). We prepare for the dovetail bit with a straight bit. One with a screw shape may have been better, as the groove left by the bit was hard-packed with sawdust that was difficult to get out, even with a screwdriver.
The clamp on the router table fence is an easy way to stop it at the right point.
We moved the clamp to the other side, and cut in the other direction.
We then ran the dovetail bit through the same path.
We ran the dovetail bit along each side of one end of each foot board as well, and voila!