You asked how the rim was constructed...
The bowl was finished from a pre-turned end grain blank, from wet Qak wood many months ago.
Held on the lathe by a spigot for the final turnings.both inside & outside, and while the bowl is still quite thick say about 18-20mm a slot of 3mm is turned into the rim from the top to depth of about 4-5mm.
The bowl is then taken from the lathe (chuck attached, never remove until completely finished) holding the chuck in a bench vice, strips of the various woods cut to the width of the slot but of different/random thicknesses (say 2mm to 8mm) keeping the length of the strip intact apply the adhesive and tap into the slot mixing the colors and thicknesses at random cutting of the strips just above the rim. the adhesive I used was Wilkinson's slow setting epoxy resin.
When completely hardened re-mount on the lathe and turn away the surplus, and turn a second slot along side and touching the first and repeat the pegging and glueing process.
Remount and finish leaving a minimum amount of wood either side of the decoration. The foot was done in a similar manner with one line of decoration visible from the side, this was made as a separate piece and attached to the bowl and finished using jamb chucking methods.