[aclindsa]

Only half of all wall outlets need the ground prong: https://www.thiings.co/things/wall-outlet

And this decidedly is not a square not: https://www.thiings.co/things/square-knot

[grues-dinner]

Some wall outlets in some regions do combine a two-prong and three-prong socket.

Though I don't know if that applies to the region that has the D: face sockets.