Currently modelling a lamp based on a small desk lamp I own, so the design isn’t one step coming out of the middle of the base, if I get stuck later I suppose I’ll just cobble together something closer to the course version.
I did an inset, extrude in, duplicate and separate for the two parts roughly equivalent to the centre hole of the example lamp for the sake of emulating the process - plus it seems to look good.
closer image for clarity:
