The round disk is like a raised coaster or a lid. The spiral was a pin tool against the clay on the wheel at the soft leatherhard stage same as for creating the "foot". Single dip in matt black.

The wheel-thrown cup/vase has the smoothest base I've made yet but the matt black needed another layer.

It's almost invisible here but I brushed a band of transparent violet alkaline glaze ~2/3 of the way up the side........creates an oil-on-water type effect. A bit thicker might work better?

I can't seem to make straight-sided cylinders - looks like a flared trouser!!

I really like black as a colour